# EPUB Publications 3.0

Recommended Specification 11 October 2011

This version
  http://www.idpf.org/epub/30/spec/epub30-publications-20111011.html
Latest version
  http://www.idpf.org/epub/30/spec/epub30-publications.html
Previous version
  http://www.idpf.org/epub/30/spec/epub30-publications-20110908.html

A diff of changes from the previous draft is available at this link.

Please refer to the errata for this document, which may include some normative corrections.

Copyright © 2010, 2011 International Digital Publishing Forum™

All rights reserved. This work is protected under Title 17 of the United States Code. Reproduction and dissemination of this work with changes is prohibited except with the written permission of the International Digital Publishing Forum (IDPF).

EPUB is a registered trademark of the International Digital Publishing Forum.

Editors

Markus Gylling, DAISY Consortium

William McCoy, International Digital Publishing Forum (IDPF)

Matt Garrish, Invited Expert

## › 1 Overview

### › 1.1 Purpose and Scope

This section is informative

This specification, EPUB Publications 3.0, defines publication-level semantics and conformance requirements for EPUB® 3, including the format of the Package Document and rules for how this document and other Publication Resources are associated to create a conforming EPUB Publication.

This specification is one of a family of related specifications that compose EPUB 3, the third major revision of an interchange and delivery format for digital publications based on XML and Web Standards. It is meant to be read and understood in concert with the other specifications that make up EPUB 3:

- The EPUB 3 Overview [EPUB3Overview], which provides an informative overview of EPUB and a roadmap to the rest of the EPUB 3 documents. The Overview should be read first.

- EPUB Content Documents 3.0 [ContentDocs30], which defines profiles of XHTML, SVG and CSS for use in the context of EPUB Publications.

- EPUB Open Container Format (OCF) 3.0 [OCF3], which defines a file format and processing model for encapsulating a set of related resources into a single-file (ZIP) EPUB Container.

- EPUB Media Overlays 3.0 [MediaOverlays30], which defines a format and a processing model for synchronization of text and audio.

This specification supersedes Open Package Format 2.0.1 [OPF2]. Refer to [EPUB3Changes] for information on differences between this specification and its predecessor.

### › 1.3 Conformance Statements

The keywords "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this document are to be interpreted as described in [RFC2119].

All sections of this specification are normative except where identified by the informative status label "This section is informative". The application of informative status to sections and appendices applies to all child content and subsections they may contain.

All examples in this specification are informative.

## › 2 EPUB Publications

This section defines conformance requirements for EPUB Publications and EPUB Reading Systems at the Publication level. Conformance requirements particular to specific Publication Resources and processing contexts are located in the specifications referenced herein.

### › 2.1 Content Conformance

An EPUB Publication must meet all of the following criteria:

All Publication Resources

  › All Publication Resources it contains must be represented in the Package Document (as defined in manifest), adhere to the constraints for Core Media Types and Fallback and be located as per Publication Resource Locations.

The Package Document

  › It must contain exactly one Package Document, which must conform to the content requirements defined in Package Document — Content Conformance.

Content Documents

  › It must contain at least one EPUB Content Document conformant to the content requirements defined in EPUB Content Documents [ContentDocs30].

The EPUB Navigation Document
EPUB Style Sheets

  › It may contain zero or more EPUB Style Sheets conformant to the content requirements defined in EPUB Style Sheets — Content Conformance [ContentDocs30].

EPUB Pronunciation Lexicons

  › It may contain zero or more PLS Documents conformant to the content requirements defined in PLS Documents — Content Conformance [ContentDocs30].

Media Overlay Documents

  › It may contain zero or more Media Overlay Documents conformant to the content requirements defined in [MediaOverlays30].

Additional Publication Resources

  › It may contain zero or more Publication Resources in addition to those listed above, each of which must adhere to the requirements in All Publication Resources.

Container

  › It must be packaged in a EPUB Container as defined in [OCF3].

### › 2.2 Reading System Conformance

An EPUB Reading System must meet all of the following criteria:

EPUB 3 Processing

  › It must process the EPUB Container as defined in [OCF3].

  › It must process the Package Document as defined in Package Document — Reading System Conformance, and honor all presentation logic expressed through the Package Document (e.g., the reading order, fallback chains and bindings).

  › It must not fail catastrophically if it encounters two distinct EPUB Publications with the same Unique Identifier.

  › Unless specified as conditional behavior in this section, it must support all Core Media Type Resources.

  › It may support an arbitrary set of Foreign Resource types, and must process fallbacks for unsupported Foreign Resources as defined in Restrictions and Fallbacks if not.

  › It must process XHTML Content Documents as defined in XHTML Content Documents — Reading System Conformance [ContentDocs30].

  › It must process SVG Content Documents as defined in SVG Content Documents — Reading System Conformance [ContentDocs30].

  › If it has a CSS Viewport, it must support visual rendering of XHTML Content Documents as defined in EPUB Style Sheets — Reading System Conformance [ContentDocs30].

  › If it has the capability to render raster images, it must support the raster image Core Media Types.

  › If it has the capability to render vector images, it must support the vector image Core Media Types.

  › If it has the capability to render pre-recorded audio, it must support the MP3 audio Core Media Type, should support the MP4 audio Core Media Type and should support Media Overlays [MediaOverlays30].

  › If it supports Text-to-Speech (TTS) rendering, it should support PLS Documents [ContentDocs30], the CSS3 Speech features of the EPUB CSS Profile [ContentDocs30] and SSML attributes [ContentDocs30] in XHTML Content Documents.

  › It must support the EPUB Canonical Fragment Identifiers scheme [EPUBCFI] for linking, and may support additional linking schemes as defined in the EPUB Linking Scheme Registry.

  ### note

  It is recommended that Reading Systems support at least one of the [H.264] and [VP8] video codecs, but this is not a conformance requirement; a Reading System may support no video codecs at all. Content creators and Reading System developers should take into consideration factors such as breadth of adoption, video playback quality, and technology usage royalty requirements when making a choice to include or implement video in either (or potentially, both) formats.

Backward Compatibility

  › It should process EPUB version 2 Publications as defined in [OPF2], [OPS2] and [OCF2].

  › It must attempt to process any Publication whose Package Document `version` attribute designates a version lower than `3.0` or which omits the `version` attribute.

Forward Compatibility

  › It should attempt to process any Publication whose Package Document `version` attribute designates a version higher than `3.0` or which omits the `version` attribute.

XML Processing

  › It must be a conformant non-validating processor [XML].

  › It must be a conformant processor as defined in [XMLNS].

  › It must support `xml-stylesheet` processing instructions [ASSOCSS], and may support additional processing instructions.

  › It must be a conformant application as defined by [XML Base].

### note

A conforming Reading System is not necessarily a single dedicated program or device, but may exist as a distributed system.

## › 3 Package Documents

### › 3.1 Introduction

This section is informative

The Package Document carries bibliographic and structural metadata about an EPUB Publication, and is thus the primary source of information about how to process and display it.

The Package Document is an XML document consisting of a set of container elements, each dedicated to housing information about a particular aspect of the Publication. These containers effectively centralize metadata for the Publication, detail the individual resources that compose it and provide reading order and other information for rendering the Publication to a User.

The following list summarizes the information a Package Document contains:

- Publication metadata — mechanisms for including and/or referencing metadata applicable to the entire Publication and particular resources within it.

- A Publication manifest — identifies (via IRI) and describes (via MIME media type) the set of resources that collectively compose the Publication.

- A spine — an ordered sequence of ID references to top-level resources in the manifest from which all other resources in the set can be reached or utilized. The spine defines the default reading order of the Publication.

- Fallback chains — an optional means for Publications to define an ordered list of top-level resources that can be considered content equivalents that a Reading System can choose between for rendering.

- Bindings — an optional means of associating script-based implementations with custom media types.

### › 3.2 Content Conformance

A Package Document must meet all of the following criteria:

Document Properties

  › It must meet the conformance constraints for XML documents defined in XML Conformance.

  › It must be valid to the Package Document schema, as defined in Appendix A, Package Document Schema, and conform to all content conformance constraints expressed in Package Document Definition.

File Properties

  › The Package Document filename should use the file extension `.opf`.

Package Documents have the MIME media type `application/oebps-package+xml` [RFC4839].

### › 3.3 Reading System Conformance

An EPUB Reading System must meet all of the following criteria:

Processing

  › It must process the Package Document in conformance with all Reading System conformance constraints expressed in Package Document Definition.

### › 3.4 Package Document Definition

All elements [XML] defined in this section are in the `http://www.idpf.org/2007/opf` namespace [XMLNS] unless otherwise specified.

#### › 3.4.1 The `package` Element

The `package` element is the root container of the Package Document and encapsulates Publication metadata and resource information.

Element Name

  `package`

Usage

  The `package` element is the root element of the Package Document.

Attributes
  `version` `[required]`

    Specifies the EPUB specification version to which the Publication conforms.

    The attribute must have the value `3.0` to indicate compliance with this version of the specification.

  `unique-identifier` `[required]`

    An IDREF [XML] that identifies the `dc:identifier` element that provides the package's preferred, or primary, identifier.

    Refer to Publication Identifiers for more information.

  `prefix` `[optional]`

    Declaration mechanism for prefixes not reserved by this specification.

    Refer to The `prefix` Attribute for more information.

  `xml:lang` `[optional]`

    Specifies the language used in the contents and attribute values of the carrying element and its descendants, as defined in section 2.12 Language Identification of [XML].

  `dir` `[optional]`

    Specifies the base text direction of the content and attribute values of the carrying element and its descendants.

    Inherent directionality specified using [Unicode] takes precedence over this attribute.

    Allowed values are `ltr` (left-to-right) or `rtl` (right-to-left).

  `id` `[optional]`

    The ID [XML] of this element, which must be unique within the document scope.

Content Model

  In this order: `metadata` `[required]`, `manifest` `[required]`, `spine` `[required]`, `guide` `[optional/deprecated]`, `bindings` `[optional]`

#### › 3.4.2 The `metadata` Element

The `metadata` element encapsulates Publication meta information.

Element Name

  `metadata`

Usage

  Required first child of `package`.

Attributes

  The `metadata` element has no attributes defined in this specification.

Content Model

  In any order: `dc:identifier` `[1 or more]`, `dc:title` `[1 or more]`, `dc:language` `[1 or more]`, `DCMES Optional Elements` `[0 or more]`, `meta` `[1 or more]`, `OPF2 meta` `[0 or more]`, `link` `[0 or more]`

The minimal required metadata that Publications must include consists of three elements from the Dublin Core Metadata Element Set [DCMES] — `title`, `identifier` and `language` — together with the `modified` property from DCMI Metadata Terms [DCTERMS]. Refer to the example at the end of this section for an instance of a complete minimal metadata set.

Additional optional metadata is expressed using the DCMES optional elements and the `meta` element.

Examples

The following example represents the minimal set of metadata that all Publications must contain.

    <package … unique-identifier="pub-id">
        …
        <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
            <dc:identifier id="pub-id">urn:uuid:A1B0D67E-2E81-4DF5-9E67-A64CBE366809</dc:identifier>
            <dc:title>Norwegian Wood</dc:title>
            <dc:language>en</dc:language>
            <meta property="dcterms:modified">2011-01-01T12:00:00Z</meta>
        </metadata>
        …
    </package>

#### › 3.4.3 The DCMES `identifier` Element

The [DCMES] `identifier` element contains a single identifier associated with the EPUB Publication, such as a UUID, DOI, ISBN or ISSN.

Element Name

  `dc:identifier`

Namespace

  `http://purl.org/dc/elements/1.1/`

Usage

  Required child of `metadata`. Repeatable.

Attributes
  `id` `[optional]`

    The ID [XML] of this element, which must be unique within the document scope.

    The `id` attribute is required on the `identifier` element containing the unique identifier. See below.

Content Model

  Text

Every `metadata` section must include at least one `identifier` element containing an unambiguous identifier for the Publication. Multiple `identifier` elements are permitted, but only one can be marked as the Unique Identifier via the `package` element `unique-identifier` attribute.

The following example shows the unique `identifier` element for a Publication.

    <package … unique-identifier="pub-id">
        <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
            <dc:identifier id="pub-id">urn:uuid:A1B0D67E-2E81-4DF5-9E67-A64CBE366809</dc:identifier>
            …
        </metadata>
    </package>

This specification makes a distinction between the Unique Identifier for an EPUB Publication and the identifier that uniquely identifies a specific version of it (i.e., to be able to differentiate EPUB Publications containing different versions of the same Manifestation). Two copies of an EPUB that are bit-for-bit identical are the same version and must retain the same last modified date. If they are not bit-for-bit identical, they represent different versions, and must have different last modified dates.

To identify a specific version of a packaged Publication, a Package Identifier can be constructed by combining the Unique Identifier with the last modified date of the Publication. Changes between versions may include minor typographic or markup corrections, without affecting the Unique Identifier. Significant revisions to the content that result in a new edition require a change of the Unique Identifier. For more information on the semantics and requirements of the Package Identifier, refer to Package Identifier.

This specification imposes no additional restrictions or requirements on identifiers except that they must be at least one character in length. It is strongly recommended that all identifiers be fully qualified URIs, however.

Reading Systems must trim all leading and trailing whitespace from the element value, as defined by the XML specification [XML], before processing the value.

To determine whether an `identifier` conforms to an established system or has been granted by an issuing authority, Reading Systems should parse the value of the property. For additional precision (e.g., if the scheme cannot be determined from the value or could lead to an ambiguous result), Authors may attach an `identifier-type` property to assist in Reading System identification. When included, the `identifier-type` property should take precedence over value parsing the `identifier`.

The following example shows how an `identifier` can be additionally marked as a DOI using the `identifier-type` property.

    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        <dc:identifier id="pub-id">urn:doi:10.1016/j.iheduc.2008.03.001</dc:identifier>
        <meta refines="#pub-id" property="identifier-type" scheme="onix:codelist5">06</meta>
        …
    </metadata>

This specification does not require or endorse the use of any specific scheme for identifiers, and imposes no restrictions or requirements on `identifier-type` identifiers beyond those specified in the property definition.

When an EPUB Publication is derived from another publication, the identifier for that source publication may be included in the Publication metadata, and must be represented using the DCMES `source` element.

#### › 3.4.4 The DCMES `title` Element

The [DCMES] `title` element represents an instance of a name given to the EPUB Publication.

Element Name

  `dc:title`

Namespace

  `http://purl.org/dc/elements/1.1/`

Usage

  Required child of `metadata`. Repeatable.

Attributes
  `id` `[optional]`

    The ID [XML] of this element, which must be unique within the document scope.

  `xml:lang` `[optional]`

    Specifies the language used in the contents and attribute values of the carrying element and its descendants, as defined in section 2.12 Language Identification of [XML].

  `dir` `[optional]`

    Specifies the base text direction of the content and attribute values of the carrying element and its descendants.

    Inherent directionality specified using [Unicode] takes precedence over this attribute.

    Allowed values are `ltr` (left-to-right) or `rtl` (right-to-left).

Content Model

  Text

Every `metadata` section must include at least one `title` element containing the title for the Publication. Multiple `title` elements are permitted, but the `title-type` property should be attached to indicate the type of title (e.g., the main title of a work, a subtitle, etc.).

The following example shows how to indicate different title types.

    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        …
        <dc:title id="t1">A Dictionary of Modern English Usage</dc:title>
        <meta refines="#t1" property="title-type">main</meta>

        <dc:title id="t2">First Edition</dc:title>
        <meta refines="#t2" property="title-type">edition</meta>

        <dc:title id="t3">Fowler's</dc:title>
        <meta refines="#t3" property="title-type">short</meta>
        …
    </metadata>

When adding the `title-type` property, Authors should designate only one `title` element as containing the main title for the Publication. If no means of determining title types is provided, or understood, Reading Systems must treat the first `title` element in document order as the main title. This specification does not define how additional `title` elements should be processed in such situations.

The optional `display-seq` property may also be attached to each `title` to indicate their primacy for display and other rendering purposes.

The following example shows how to indicate display sequence.

    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        …
        <dc:title id="t1">The Red and the Black</dc:title>
        <meta refines="#t1" property="title-type">main</meta>
        <meta refines="#t1" property="display-seq">1</meta>

        <dc:title id="t2">A Chronicle of the Nineteenth Century</dc:title>
        <meta refines="#t2" property="title-type">subtitle</meta>
        <meta refines="#t2" property="display-seq">2</meta>

        <dc:title id="t3">A Chronicle of 1830</dc:title>
        <meta refines="#t3" property="title-type">subtitle</meta>
        <meta refines="#t3" property="display-seq">3</meta>
        …
    </metadata>

This specification imposes no additional restrictions or requirements on titles except that they must be at least one character in length.

Reading Systems must trim all leading and trailing whitespace from the element value, as defined by the XML specification [XML], before processing the value.

Examples

The following example shows how the title "THE LORD OF THE RINGS, Part One: The Fellowship of the Ring" could be classified.

    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        <dc:title id="t1">The Fellowship of the Ring</dc:title>
        <meta refines="#t1" property="title-type">main</meta>

        <dc:title id="t2">The Lord of the Rings</dc:title>
        <meta refines="#t2" property="title-type">collection</meta>
        <meta refines="#t2" property="group-position">1</meta>

        <dc:title id="t3">THE LORD OF THE RINGS, Part One: The Fellowship of the Ring</dc:title>
        <meta refines="#t3" property="title-type">extended</meta>
        …
    </metadata>

The following example shows how the complex title "The Great Cookbooks of the World: Mon premier guide de cuisson, un Mémoire. The New French Cuisine Masters, Volume Two. Special Anniversary Edition" could be classified.

    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        <dc:title id="t1" xml:lang="fr">Mon premier guide de cuisson, un Mémoire</dc:title>
        <meta refines="#t1" property="title-type">main</meta>
        <meta refines="#t1" property="display-seq">2</meta>

        <dc:title id="t2">The Great Cookbooks of the World</dc:title>
        <meta refines="#t2" property="title-type">collection</meta>
        <meta refines="#t2" property="display-seq">1</meta>

        <dc:title id="t3">The New French Cuisine Masters</dc:title>
        <meta refines="#t3" property="title-type">collection</meta>
        <meta refines="#t3" property="group-position">2</meta>
        <meta refines="#t3" property="display-seq">3</meta>

        <dc:title id="t4">Special Anniversary Edition</dc:title>
        <meta refines="#t4" property="title-type">edition</meta>
        <meta refines="#t4" property="display-seq">4</meta>

        <dc:title id="t5">The Great Cookbooks of the World:
            Mon premier guide de cuisson, un Mémoire.
            The New French Cuisine Masters, Volume Two.
            Special Anniversary Edition</dc:title>
        <meta refines="#t5" property="title-type">extended</meta>
        …
    </metadata>

#### › 3.4.5 The DCMES `language` Element

The [DCMES] `language` element specifies the language of the Publication content.

Element Name

  `dc:language`

Namespace

  `http://purl.org/dc/elements/1.1/`

Usage

  Required child of `metadata`.

Attributes
  `id` `[optional]`

    The ID [XML] of this element, which must be unique within the document scope.

Content Model

  Text

Every `metadata` section must include at least one `language` element with a value conforming to [RFC5646].

The following example shows a Publication is in U.S. English.

    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        …
        <dc:language>en-US</dc:language>
        …
    </metadata>

Additional `language` elements may be included for multilingual Publications, but each element's value must conform to [RFC5646].

Reading Systems must trim all leading and trailing whitespace from the element value, as defined by the XML specification [XML], before processing the value.

#### › 3.4.6 The DCMES Optional Elements

All elements from the [DCMES] element set — except for `identifier`, `language` and `title`, as defined above — are designated as optional. These elements all conform to the following generalized definition:

Element Name

  `contributor | coverage | creator | date | description | format | publisher | relation | rights | source | subject | type`

Namespace

  `http://purl.org/dc/elements/1.1/`

Usage

  Optional child of `metadata`. Repeatable.

Attributes
  `id` `[optional]`

    The ID [XML] of this element, which must be unique within the document scope.

  `xml:lang`* `[optional]`

    Specifies the language used in the contents and attribute values of the carrying element and its descendants, as defined in section 2.12 Language Identification of [XML].

  `dir`* `[optional]`

    Specifies the base text direction of the content and attribute values of the carrying element and its descendants.

    Inherent directionality specified using [Unicode] takes precedence over this attribute.

    Allowed values are `ltr` (left-to-right) or `rtl` (right-to-left).

Content Model

  Text

* The `xml:lang` and `dir` attributes are permitted only on the following elements: `contributor`, `coverage`, `creator`, `description`, `publisher`, `relation`, `rights` and `subject`.

The value of all optional [DCMES] elements must be at least one character in length.

Reading Systems must trim all leading and trailing whitespace from the element value, as defined by the XML specification [XML], before processing the value.

Except as detailed below, this specification does not modify the [DCMES] definitions for these elements.

The DCMES `contributor` Element

The `contributor` element is used to represent the name of a person, organization, etc. that played a secondary role in the creation of the content of a Publication.

The use of the `contributor` element is identical to the use of the `creator` element in all other respects, as detailed in the next section.

The DCMES `creator` Element

The `creator` element represents the name of a person, organization, etc. responsible for the creation of the content of a Publication. The `role` property can be attached to the element to indicate the function the creator played in the creation of the content.

The following example shows how to represent a `creator` as an author using a MARC relators term.

    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        …
        <dc:creator id="creator">Haruki Murakami</dc:creator>
        <meta refines="#creator" property="role" scheme="marc:relators" id="role">aut</meta>
        …
    </metadata>

The `creator` element should contain the name of the creator as a Reading System will present it to a User. The `file-as` property may be attached to include a normalized form of the name, and the `alternate-script` property can be used to represent a creator's name in another language or script.

The following example shows the different ways a creator's name can be included to facilitate processing and rendering.

    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        …
        <dc:creator id="creator">Haruki Murakami</dc:creator>
        <meta refines="#creator" property="role" scheme="marc:relators" id="role">aut</meta>
        <meta refines="#creator" property="alternate-script" xml:lang="ja">村上 春樹</meta>
        <meta refines="#creator" property="file-as">Murakami, Haruki</meta>
        …
    </metadata>

If a Publication has more than one creator, each should be included in a separate `creator` element. The order in which to render the `creator` names should be specified using the `display-seq` property.

The following example shows how to indicate the display order for `creator` elements.

    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        …
        <dc:creator id="creator01">Lewis Carroll</dc:creator>
        <meta refines="#creator01" property="role" scheme="marc:relators">aut</meta>
        <meta refines="#creator01" property="display-seq">1</meta>

        <dc:creator id="creator02">John Tenniel</dc:creator>
        <meta refines="#creator02" property="role" scheme="marc:relators">ill</meta>
        <meta refines="#creator02" property="display-seq">2</meta>
        …
    </metadata>

If no means of establishing the primacy of creators is included, Reading Systems must use the order of `creator` elements.

Secondary contributors should be represented using DCMES `contributor` elements.

The DCMES `date` Element

The `date` element must only be used to define the publication date of the EPUB Publication. The publication date is not the same as the last modified date (the last time the content was changed), which must be included using the [DCTERMS] `modified` property.

For compliance with EPUB 2 Reading Systems, the date string should conform to Date and Time Formats.

The following example shows a publication date.

    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        …
        <dc:date>2000-01-01T00:00:00Z</dc:date>
        …
    </metadata>

Additional dates should be expressed using the specialized date properties available in the [DCTERMS] vocabulary, or similar.

The publication date may be common to all instances of a Publication or may change from instance to instance (if the Publication gets generated on demand, for example).

Only one `date` element is allowed.

The DCMES `source` Element

The `source` element must only be used to specify the identifier of the source publication from which this EPUB Publication is derived.

The following example shows the ISBN identifier for a Publication together with the source ISBN identifier for the print work it was derived from.

    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        …
        <dc:identifier id="isbn-id">urn:isbn:9780101010101</dc:identifier>
        <meta refines="#isbn-id" property="identifier-type" scheme="onix:codelist5">15</meta>

        <dc:source id="src-id">urn:isbn:9780375704024</dc:source>
        <meta refines="#src-id" property="identifier-type" scheme="onix:codelist5">15</meta>
        …
    </metadata>

The `source` element allows the print source of the pagination of a Publication to be determined.

Only one `source` element is allowed.

The DCMES `type` Element

The `type` element is used to indicate that the given Publication is of a specialized type (e.g., annotations packaged in EPUB format or a dictionary).

This specification does not define values for this element, however. The development of specialized Publication types, and the assignment of formal identifiers to represent them, will occur independently of this specification.

Only one `type` element is allowed.

#### › 3.4.7 The `meta` Element

The `meta` element provides a generic means of including package metadata, allowing the expression of primary metadata about the package or content and refinement of that metadata.

Element Name

  `meta`

Usage

  As child of the `metadata` element. Repeatable.

Attributes
  `property` `[required]`

    A property.

    Refer to Vocabulary Association Mechanisms for more information.

  `refines` `[context dependent]`

    Identifies the expression or resource augmented by this element. The value of the attribute must be a relative IRI [RFC3987] pointing to the resource or element it describes.

    The `refines` attribute is optional depending on the type of metadata being expressed. When omitted, the `meta` element defines a primary expression.

  `id` `[optional]`

    The ID [XML] of this element, which must be unique within the document scope.

  `scheme` `[optional]`

    A property data type value indicating the source the value of the element is drawn from.

Content Model

  Text

Each `meta` element defines a metadata expression, where the `property` attribute defines the statement being made in the expression and the text content of the element represents the assertion.

This specification defines two types of metadata expressions that can be defined using the `meta` element:

- A primary expression is one in which the expression defined in the `meta` element establishes some aspect of the EPUB Publication. A `meta` element that omits a `refines` attribute defines a primary expression.

- A subexpression is one in which the expression defined in the `meta` element enhances the meaning of the expression or resource referenced in its `refines` attribute. A subexpression may refine a media clip, for example, by expressing its duration, or refine a creator or contributor expression by defining the person's role.

  Subexpressions are not limited to refining only primary expressions and resources; they may be used to refine the meaning of other subexpressions, thereby creating chains of information.

### note

All of the [DCMES] elements represent primary expressions, and permit refinement by `meta` element subexpressions.

This specification reserves a set of vocabularies for use in the `property` attribute, but terms from any vocabulary may be used so long as a prefix is declared for the vocabulary.

The `scheme` attribute can be used to identify the system or scheme that a `meta` element's value is drawn from. The value of the scheme attribute is a property data type that resolves to the resource that defines the scheme.

The following example shows how a subexpression can be attached to an `creator` to indicate it represents an author. The `scheme` indicates the value is drawn from the MARC relators terms.

    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        …
        <dc:creator id="creator">Haruki Murakami</dc:creator>
        <meta refines="#creator" property="role" scheme="marc:relators" id="role">aut</meta>
        …
    </metadata>

If a Reading System does not recognize the `scheme` attribute value, it should treat the value of the element as a string.

Reading Systems should ignore all `meta` elements whose `property` attributes define expressions they do not recognize. A Reading System must not fail when encountering unknown expressions.

In order to ensure that a Package Identifier can be constructed, the `metadata` element must contain exactly one `meta` element defining a [DCTERMS] `modified` property for the Publication. Additional `modified` properties may be included, but they must have a different subject (i.e., they must include a `refines` attribute pointing to an element or resource).

Every `meta` element must express a value that is at least one character in length after whitespace normalization.

Unless an individual property explicitly defines a different whitespace normalization algorithm, Reading Systems must trim all leading and trailing whitespace from the `meta` element values, as defined by the XML specification [XML], before further processing them.

Examples

The following example represents a more complete set of metadata that typical Publications will contain.

    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        …
        <dc:identifier id="pub-id">urn:uuid:A1B0D67E-2E81-4DF5-9E67-A64CBE366809</dc:identifier>
        <meta refines="#pub-id" property="identifier-type" scheme="xsd:string">uuid</meta>

        <dc:identifier id="isbn-id">urn:isbn:9780101010101</dc:identifier>
        <meta refines="#isbn-id" property="identifier-type" scheme="onix:codelist5">15</meta>

        <dc:source id="src-id">urn:isbn:9780375704024</dc:source>
        <meta refines="#src-id" property="identifier-type" scheme="onix:codelist5">15</meta>

        <dc:title id="title">Norwegian Wood</dc:title>
        <meta refines="#title" property="title-type">main</meta>

        <dc:language>en</dc:language>

        <dc:creator id="creator">Haruki Murakami</dc:creator>
        <meta refines="#creator" property="role" scheme="marc:relators" id="role">aut</meta>
        <meta refines="#creator" property="alternate-script" xml:lang="ja">村上 春樹</meta>
        <meta refines="#creator" property="file-as">Murakami, Haruki</meta>

        <meta property="dcterms:modified">2011-01-01T12:00:00Z</meta>

    </metadata>

The following example shows an identifier that has been issued by a metadata authority.

    <package version="3.0"
             unique-identifier="pub-id"
             xmlns="http://www.idpf.org/2007/opf">
        <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
            <dc:identifier id="pub-id">urn:uuid:1234-5678</dc:identifier>
            <dc:identifier id="isbn-id">urn:isbn:9780101010101</dc:identifier>

            <meta refines="#isbn-id" property="meta-auth" id="meta-authority-01">Metadata Authority Inc.</meta>
            <link refines="#meta-authority-01" rel="xml-signature" href="../META-INF/Signatures.xml#MAI-Signature"/>
            …
        </metadata>
    </package>

    <!-- in Signatures.xml -->
    <signatures>
        <Signature Id="MAI-Signature" xmlns="http://www.w3.org/2000/09/xmldsig#">
            …
        </Signature>
    </signatures>

#### › 3.4.8 The `meta` Element (OPF2) [OBSOLETE]

The `meta` element defined in [OPF2] has been obsoleted and replaced by the new `meta` element, but may be included as an optional repeatable child of the `metadata` element for forwards compatibility purposes.

EPUB 3 Reading Systems must ignore this element.

#### › 3.4.9 The `link` Element

The `link` element is used to associate resources with a Publication, such as metadata records.

Element Name

  `link`

Usage

  As a child of `metadata`. Repeatable.

Attributes
  `href` `[required]`

    An absolute or relative IRI reference [RFC3987] to a resource.

  `rel` `[required]`

    A space-separated list of property values.

  `id` `[optional]`

    The ID [XML] of this element, which must be unique within the document scope.

  `refines` `[optional]`

    Identifies the expression or resource augmented by this element. The value of the attribute must be a relative IRI [RFC3987] pointing to the resource or element it describes.

    When the `refines` attribute is omitted, the expression applies to the EPUB Publication as a whole.

  `media-type` `[optional]`

    A media type [RFC2046] that specifies the type and format of the resource referenced by this `link`.

Content Model

  Empty

The `metadata` element may contain zero or more `link` elements.

The `href` attribute of the `link` element identifies the location of the resource — inclusion of which is optional in the container file — and the `rel` attribute defines the nature of the resource (i.e., its relation to the Publication or property specified in the `refines` attribute). Reading Systems are not required to dereference these resources. Refer to Metadata `link` Properties for the list of resource types that are recognized by this specification.

Resources identified by the `link` element `href` attribute must not be represented as `item`s in the manifest.

When the `link` element references a metadata record, precedence must be given to metadata defined inline in the Package Document `metadata` element in the case of conflicts.

The optional `refines` attribute can be attached when the referenced resource applies to another metadata item (e.g., to tie an XML Signature [XML DSIG Core] to a metadata authority). The resource applies to the Publication as a whole when the attribute is not present.

If a Reading System does not recognize the relationship of the resource as defined in the `rel` attribute, it should ignore the `link` element.

Examples

The following example shows the `link` element used to associate three metadata resources with the Publication: an ONIX record, an XMP record, and a link to an informational web page. Note that as `foaf` is not a predefined prefix, the metadata extensibility mechanism is employed to associate the vocabulary.

    <package … prefix="foaf: http://xmlns.com/foaf/spec/">
        <metadata>
            …
            <link rel="onix-record" href="http://example.org/onix/12389347"/>
            <link rel="xmp-record" href="http://example.org/xmp/12389347"/>
            <link rel="foaf:homepage" href="http://example.org/book-info/12389347" />
            …
        </metadata>
        …
    </package>

#### › 3.4.10 The `manifest` Element

The `manifest` element provides an exhaustive list of the Publication Resources that constitute the EPUB Publication, each represented by an `item` element.

Element name

  `manifest`

Usage

  Required second child of `package`, following `metadata`.

Attributes
  `id` `[optional]`

    The ID [XML] of this element, which must be unique within the document scope.

Content Model

  One or more `item` elements `[required]`

### note

This specification supports internationalized resource naming, so elements and attributes that reference Publication Resources accept IRIs as their value. For compatibility with older Reading Systems that only accept URIs, resource names should be restricted to the ASCII character set.

#### › 3.4.11 The `item` Element

The `item` element represents a Publication Resource.

Element Name

  `item`

Usage

  As a child of `manifest`. Repeatable.

Attributes
  `id` `[required]`

    The ID [XML] of this element, which must be unique within the document scope.

  `href` `[required]`

    An IRI [RFC3987] specifying the location of the Publication Resource described by this `item`.

  `media-type` `[required]`

    A media type [RFC2046] that specifies the type and format of the Publication Resource described by this `item`.

  `fallback` `[conditionally required]`

    An IDREF [XML] that identifies the fallback for a non-Core Media Type.

    Refer to Manifest Fallbacks for more information.

  `properties` `[optional]`

    A space-separated list of property values.

    Refer to Manifest `item` Properties for a set of properties defined by this specification.

  `media-overlay` `[optional]`

    An IDREF [XML] that identifies the Media Overlay Document for the resource described by this `item`.

    Refer to Packaging [MediaOverlays30] for more information.

Content Model

  Empty

Each `item` element in the `manifest` identifies a Publication Resource by the IRI provided in its `href` attribute. The IRI may be absolute or relative. In the case of relative IRIs, Reading Systems must use the IRI of the Package Document as the base when resolving these to absolute IRIs. The resulting absolute IRI must be unique within the `manifest` scope.

All Publication Resources must be referenced from the `manifest`, regardless of whether they are included in the EPUB Container or made available remotely. Refer to Publication Resource Locations for media type-specific requirements regarding resource locations.

The Publication Resource identified by an `item` element must conform to the applicable specification(s) as inferred from the MIME media type provided in the `media-type` attribute. Core Media Type Resources must use the media type designated in EPUB Core Media Types.

All Foreign Resources must provide a fallback as defined in Restrictions and Fallbacks.

All Publication Resources must declare any applicable descriptive metadata properties as defined in Manifest `item` Properties via the `item` element `properties` attribute. Exactly one `item` must be declared as the EPUB Navigation Document using the `nav` property.

Reading Systems must ignore all descriptive metadata properties that they do not recognize.

The manifest is not self-referencing: it must not include an `item` element that refers to the Package Document itself.

### note

The order of `item` elements in the manifest is not significant. The presentation sequence of content documents is provided in the `spine`.

Examples

The following example shows a `manifest` that only contains Core Media Type Resources.

    <manifest>
        <item id="nav"
              href="nav.xhtml"
              properties="nav"
              media-type="application/xhtml+xml"/>
        <item id="intro"
              href="intro.xhtml"
              media-type="application/xhtml+xml"/>
        <item id="c1"
              href="chap1.xhtml"
              media-type="application/xhtml+xml"/>
        <item id="c1-answerkey"
              href="chap1-answerkey.xhtml"
              media-type="application/xhtml+xml"/>
        <item id="c2"
              href="chap2.xhtml"
              media-type="application/xhtml+xml"/>
        <item id="c2-answerkey"
              href="chap2-answerkey.xhtml"
              media-type="application/xhtml+xml"/>
        <item id="c3"
              href="chap3.xhtml"
              media-type="application/xhtml+xml"/>
        <item id="c3-answerkey"
              href="chap3-answerkey.xhtml"
              media-type="application/xhtml+xml"/>
        <item id="notes"
              href="notes.xhtml"
              media-type="application/xhtml+xml"/>
        <item id="cover"
              href="./images/cover.svg"
              properties="cover-image"
              media-type="image/svg+xml"/>
        <item id="f1"
              href="./images/fig1.jpg"
              media-type="image/jpeg"/>
        <item id="f2"
              href="./images/fig2.jpg"
              media-type="image/jpeg"/>
        <item id="css"
              href="./style/book.css"
              media-type="text/css"/>
        <item id="pls"
              href="./speech/dict.pls"
              media-type="application/pls+xml"/>
    </manifest>

The following example shows a `manifest` that references two Foreign Resources, and therefore uses the fallback chain mechanism to supply content alternatives. The fallback chain terminates with a Core Media Type.

    <manifest>
        <item id="item1"
              href="chap1_docbook.xml"
              media-type="application/docbook+xml"
              fallback="fall1"/>
        <item id="fall1"
              href="chap1.xml"
              media-type="application/z3986-auth+xml"
              fallback="fall2" />
        <item id="fall2"
              href="chap1.xhtml"
              media-type="application/xhtml+xml"/>
        …
    </manifest>

### note

Refer also to the Manifest item properties examples for use of the `properties` attribute.

#### › 3.4.12 The `spine` Element

The `spine` element defines the default reading order of the EPUB Publication content by defining an ordered list of manifest `item` references.

Element name

  `spine`

Usage

  Required third child of `package`, following `manifest`.

Attributes
  `id` `[optional]`

    The ID [XML] of this element, which must be unique within the document scope.

  `toc` `[optional]`

    An IDREF [XML] that identifies the manifest `item` that represents the superseded `NCX`.

    Refer to NCX Superseded for more information.

  `page-progression-direction` `[optional]`

    The global direction in which the Publication content flows.

    Allowed values are `ltr` (left-to-right), `rtl` (right-to-left) and `default`.

    When the `default` value is specified, the Author is expressing no preference and the Reading System may chose the rendering direction. This value must be assumed when the attribute is not specified.

Content Model

  Multiple `itemref` elements `[required]`

The `spine` represents an ordered subset of the Publication Resources listed in the `manifest`, with content items not being referenced being ancillary to those that do.

Reading Systems must provide a means of rendering a Publication in the order defined by the `spine`, which includes: 1) recognizing the first primary (`linear='yes'`) `item` in the `spine` as the beginning of the main reading order of the Publication; and, 2) rendering successive primary items in the order given in the `spine`.

### note

Although the `page-progression-direction` attribute sets the global flow direction for a Publication, individual Content Documents and parts of Content Documents may override this setting (e.g., via the `direction` and `writing-mode` CSS properties). Reading Systems may also provide mechanisms to override the default direction (e.g., buttons or settings that allow the application of alternate style sheets).

NCX Superseded

The NCX feature defined in [OPF2] is superseded by the EPUB Navigation Document [ContentDocs30]. EPUB 3 Publications may include an NCX (as defined in OPF 2.0.1) for EPUB 2 Reading System forwards compatibility purposes, but EPUB 3 Reading Systems must ignore the NCX in favor of the EPUB Navigation Document.

### note

As the EPUB 2 NCX and the EPUB 3 Navigation Document use different mechanisms for identification in the Package Document (the spine `toc` attribute and the `nav` property on the manifest `item` element, respectively) they can co-exist without conflict in an EPUB 3 Publication.

#### › 3.4.13 The `itemref` Element

The child `itemref` elements of the `spine` represent a sequential list of Publication Resources (typically EPUB Content Documents). The order of the `itemref` elements defines the default reading order of the Publication.

Element Name

  `itemref`

Usage

  As a child of `spine`. Repeatable.

Attributes
  `idref` `[required]`

    An IDREF [XML] that identifies a manifest item.

  `linear` `[optional]`

    Specifies whether the referenced content is primary.

    The value of the attribute must be `yes` or `no`. The default value is `yes`.

  `id` `[optional]`

    The ID [XML] of this element, which must be unique within the document scope.

  `properties` `[optional]`

    A space-separated list of property values.

    Refer to Spine `itemref` Properties for a set of properties defined by this specification.

Content Model

  Empty

Each `itemref` element must reference an `item` in the manifest via its `idref` attribute.

Each referenced manifest `item` must be either a) an EPUB Content Document or b) another type of Publication Resource which, regardless of whether it is a Core Media Type Resource or a Foreign Resource, must include an EPUB Content Document in its fallback chain.

### note

Although the EPUB Navigation Document is required in EPUB Publications, it is optional to include it in the `spine`.

The `itemref` element `linear` attribute indicates whether referenced item is considered primary (`yes`) or auxiliary (`no`) in the `spine`. This attribute may be used to enable Reading Systems to distinguish presentation of body content from supplementary content which might be, for example, presented in a popup window or omitted from an aural rendition.

Any applicable descriptive metadata properties, such as those defined in the Spine `itemref` Properties, should be declared via the `properties` attribute.

Reading Systems must ignore all metadata properties expressed in the `properties` attribute that they do not recognize.

Examples

The following example shows a `spine` element corresponding to the manifest example above.

    <spine page-progression-direction="ltr">
        <itemref idref="intro"/>
        <itemref idref="c1"/>
        <itemref idref="c1-answerkey" linear="no"/>
        <itemref idref="c2"/>
        <itemref idref="c2-answerkey" linear="no"/>
        <itemref idref="c3"/>
        <itemref idref="c3-answerkey" linear="no"/>
        <itemref idref="notes" linear="no"/>
    </spine>

#### › 3.4.14 The `guide` Element [DEPRECATED]

The `guide` element [OPF2] is deprecated in favor of the `landmarks` feature in the EPUB Navigation Document. Refer to The landmarks nav Element [ContentDocs30] for more information.

Authors may include the `guide` element in the Package Document for EPUB 2 Reading System forwards compatibility purposes. EPUB 3 Reading Systems must ignore the `guide` element when provided in EPUB 3 Publications whose EPUB Navigation Document includes the `landmarks` feature.

#### › 3.4.15 The `bindings` Element

The `bindings` element defines a set of custom handlers for media types not supported by this specification.

Element Name

  `bindings`

Usage

  Optional fourth or fifth child of `package`, following `spine` or `guide`.

Attributes

  None.

Content Model

  One or more `mediaType` elements `[required]`

The `package` element may contain at most one `bindings` element.

The `bindings` element provides a means for Authors to include more sophisticated fallbacks than would otherwise be possible with the [HTML5] `object` element's intrinsic fallback mechanisms. When present, Reading Systems that support scripting must utilize the `bindings` element to handle `object` elements that reference unsupported media types.

Each of the `bindings` element's child `mediaType` elements defines a unique handler for one of the foreign media types referenced in the Publication's XHTML Content Documents.

When an unsupported media type is encountered during processing of a document, the Reading System must look up the handler in the `bindings` element by checking the `media-type` attribute of each `mediaType` element for a match (and before attempting any other type of fallback processing). If a match is found, the XHTML Content Document referenced in the element's `handler` attribute must be instantiated instead of the referenced resource. If no match is found, the Reading System should continue with normal fallback processing (i.e., check for an intrinsic fallback for the `object`).

The Reading System must instantiate the designated handler as if it had been referenced from the `object` element's `data` attribute with the following parameters:

`src`

  the value of which must be an IRI [RFC3987] to the resource (i.e., the value of the `object` element's `data` attribute).

`type`

  the value of which must be the resource media type (i.e., the value of the `object` element's `media-type` attribute).

Any additional `param` children of the `object` element must be similarly added as parameters using the `param`'s `name` attribute as the new parameter name and its `value` attribute as the new value.

For example, the following `object` element containing a foreign media type:

    <object data="horse.ogg" media-type="audio/ogg"/>
        <param name="autoplay" value="false">
    </object>

would result in the following query string being sent to the handler XHTML Content Document after processing:

    src=horse.ogg&type=audio/ogg&autoplay=false

All IRI reserved characters, plus the characters `<`, `>`, `"`, `space`, `{`, `}`, `|`, `\`, `^` and ```, in the generated query string must be encoded and decoded as per [RFC3987].

`object` elements that reference media types handled by the `bindings` element are only processed in spine-referenced XHTML Content Documents (i.e., they are ignored in container-constrained scripting contexts).

Example

The following partial example illustrates how bindings can be used to provide a slideshow.

Consider a Publication with the following Package Document:

    <package …>
        …
        <manifest>
            <item id="pict1"
                href="images/Pict1.jpg"
                media-type="image/jpeg"/>
            …
            <item id="content"
                href="content.xhtml"
                media-type="application/xhtml+xml"/>
            <item id="impl"
                href="impl.xhtml"
                media-type="application/xhtml+xml"
                properties="scripted"/>
            <item id="slideshow"
                href="slideshow.xml"
                media-type="application/x-demo-slideshow"/>
        </manifest>

        <bindings>
            <mediaType handler="impl"
                media-type="application/x-demo-slideshow"/>
        </bindings>
        …
    </package>

and the following content in the file `content.xhtml`:

    <html …>
        …
        <body>
            …
            <object data="slideshow.xml"
                type="application/x-demo-slideshow">
                <img src="images/Pict1.jpg"/>
                <img src="images/Pict2.jpg"/>
                <img src="images/Pict3.jpg"/>
                <img src="images/Pict4.jpg"/>
            </object>
            …
        </body>
    </html>

and the following content in the file `slideshow.xml`:

    <slides>
        <slide src="images/Pict1.jpg" dur="3"/>
        <slide src="images/Pict2.jpg" dur="3"/>
        <slide src="images/Pict3.jpg" dur="3"/>
        <slide src="images/Pict4.jpg" dur="3"/>
    </slides>

Depending on the capabilities of the User's Reading System, they will see one of the following renditions of the slideshow:

- If the Reading System supports the native slideshow format, it will render a rotating set of images as specified in `slideshow.xml`.

- If the Reading System cannot support the slideshow media type but supports scripting, it can check the `bindings` element in the Package Document for a scripted fallback. There it will find a reference to the `item` element containing the handler document (`impl.xhtml`). The Reading System can now load this document to render a JavaScripted equivalent of the slideshow (source not shown).

- If the Reading System does not support the slideshow media type and also does not support scripting, it will use the fallback images specified in the `object` element to show a static set of all the images.

#### › 3.4.16 The `mediaType` Element

The `mediaType` element associates a Foreign Resource media type with a handler XHTML Content Document.

Element Name

  `mediaType`

Usage

  As a child of `bindings`. Repeatable.

Attributes
  `media-type` `[required]`

    A media type [RFC2046] that specifies the type and format of the resource to be handled.

  `handler` `[required]`

    An IDREF [XML] that identifies the manifest XHTML Content Document to be invoked to handle content of the type specified in this element

Content Model

  Empty

Each child `mediaType` of a `bindings` element must define a unique content type in its `media-type` attribute, and the media type specified must not be a Core Media Type.

The required `handler` attribute must reference the ID [XML] of an `item` in the `manifest` of the default implementation for this media type. The referenced `item` must be an XHTML Content Document.

All XHTML Content Documents designated as handlers must have the `scripted` property set in their manifest `item`'s `properties` attribute.

## › 4 Package Metadata

### › 4.1 Publication Identifiers

#### › 4.1.1 Unique Identifier

The Package Document's author is responsible for including a primary identifier that is unique to one and only one particular EPUB Publication. This Unique Identifier, whether chosen or assigned, must be stored in a `dc:identifier` element in the Package metadata and be referenced as the Unique Identifier in the `package` element `unique-identifier` attribute.

Although not static, changes to the Unique Identifier for a Publication should be made as infrequently as possible. New identifiers should not be issued when updating metadata, fixing errata or making other minor changes to the Publication.

#### › 4.1.2 Package Identifier

The Unique Identifier of an EPUB Publication typically should not change with each minor revision to the package or its contents, as Unique Identifiers are intended to have maximal persistence both for referencing and distribution purposes. Each release of a Publication normally requires that the new version be uniquely identifiable, however, which results in the contradictory need for reliable Unique Identifiers that are changeable.

To redress this problem of identifying minor modifications and releases without changing the Unique Identifier, this specification defines the semantics for a Package Identifier, or means of distinguishing and sequentially ordering Publications with the same Unique Identifier. The Package Identifier is not an actual property in the package `metadata` section, but is a value that can be obtained from two required pieces of metadata: the Unique Identifier and the last modification date of the Publication.

When the taken together, the combined value represents a unique identity that can be used to distinguish any particular version of an EPUB Manifestation from another. To ensure that a Package Identifier can be constructed, the Publication must include exactly one [DCTERMS] `modified` property containing the last modification date (see meta). The value of this property must be an XML Schema [XSD-DATATYPES] dateTime conformant date of the form:

    CCYY-MM-DDThh:mm:ssZ

The modification date must be expressed in Coordinated Universal Time (UTC) and must be terminated by the `Z` time zone indicator.

Although not a part of the package metadata, for referencing and other purposes this specification requires that all string representations of the identifier be constructed using the at sign (`@`) as the separator (i.e., of the form "id`@`date"). Whitespace must not be included when concatenating the strings.

The following example shows how a Unique Identifier and modification date are combined to form the Package Identifier.

    <metadata xmlns:dc="http://purl.org/dc/elements/1.1/">
        <dc:identifier id="pub-id">urn:uuid:A1B0D67E-2E81-4DF5-9E67-A64CBE366809</dc:identifier>
        <meta property="dcterms:modified">2011-01-01T12:00:00Z</meta>
        …
    </metadata>

    results in the Package ID:

    urn:uuid:A1B0D67E-2E81-4DF5-9E67-A64CBE366809@2011-01-01T12:00:00Z

Note that it is possible that the separator character may occur in the Unique Identifier, as these identifiers may be any string value. The Package Identifier consequently must be split on the last instance of the at sign when decomposing it into its component parts.

The Package Identifier does not supersede the Unique Identifier, but represents the means by which different versions of the same Publication can be distinguished and identified in distribution channels and by Reading Systems. The sequential, chronological order inherent in the required format of the timestamp also places Publications in order without requiring knowledge of the exact identifier that came before.

The Package Identifier consequently allows a set of Publications to be inspected to determine if they represent the same version of the same Publication, different versions of a single Publication, or any combination of differing and similar Publications.

### › 4.2 Vocabulary Association Mechanisms

#### › 4.2.1 Overview

This section is informative

The `property`, `properties`, `rel` and `scheme` attributes use the property data type to represent terms from metadata vocabularies. Similar to a CURIE [RDFa10], the property data type represents an IRI [RFC3987] in compact form and simplifies the authoring of metadata from standardized vocabularies.

A property value is an expression that consists of a prefix and a reference, where the prefix — whether literal or implied — is a shorthand mapping of an IRI that typically resolves to a term vocabulary. When the prefix is converted to its IRI representation and combined with the reference, the resulting IRI normally resolves to a fragment within that vocabulary that contains human- and/or machine-readable information about the term.

To assist Reading Systems in processing property values, the means of establishing the IRI a prefix maps to is required, and this specification defines three such mechanisms:

- a default vocabulary — defines the mapping when a property value does not include a prefix;

- a set of reserved prefixes — these mappings are predefined (i.e., all Reading Systems recognize them) and can be used without having to be declared; and

- the `prefix` attribute — a declarative means of creating new prefix mappings on the root `package` element.

#### › 4.2.2 Default Vocabulary

The default vocabulary is a vocabulary that does not require a prefix to be declared in order to use its terms in package metadata, and whose terms must always be unprefixed.

To facilitate the inclusion of package metadata, this specification defines the Package Metadata Vocabulary as the default vocabulary for Package Documents.

If a property value does not include a prefix, the IRI [RFC3987] stem `http://idpf.org/epub/vocab/package/#` must be used to generate the resulting IRI.

The IRI associated with the Package Metadata Vocabulary must not be assigned a prefix using the `prefix` attribute.

#### › 4.2.3 Reserved Vocabularies

This specification exclusively defines the following set of prefixes for use in package metadata.

Reserved metadata prefixes
Prefix | IRI
--- | ---
dcterms | http://purl.org/dc/terms/
marc | http://id.loc.gov/vocabulary/
media | http://www.idpf.org/epub/vocab/overlays/#
onix | http://www.editeur.org/ONIX/book/codelists/current.html#
xsd | http://www.w3.org/2001/XMLSchema#

The prefixes listed in the previous table must not be redeclared using the `prefix` attribute declaration mechanism. Similarly, the IRIs associated with each prefix must not be assigned to another prefix.

#### › 4.2.4 The `prefix` Attribute

The `prefix` attribute defines additional prefix mappings not reserved by the specification.

The value of the `prefix` attribute is a whitespace-separated list of one or more prefix-to-IRI mappings of the form:

(EBNF productions ISO/IEC 14977)
prefixes | `=` | mapping , { whitespace, { whitespace } , mapping } ; |
mapping | `=` | prefix , ":" , space , { space } , ? xsd:anyURI ? ; |
prefix | `=` | ? xsd:NCName ? ; |
space | `=` | #x20 ; |
whitespace | `=` | (#x20 | #x9 | #xD | #xA) ; |

The following example shows prefixes for the Friend of a Friend (`foaf`) and DBPedia (`dbp`) vocabularies being declared using the `prefix` attribute.

    <package …
    	prefix="foaf: http://xmlns.com/foaf/spec/
    		 dbp: http://dbpedia.org/ontology/">
    	…
    </package>

The `prefix` attribute must not be used to redefine the default vocabulary or the predefined prefixes.

The prefix '_' is reserved for future compatibility with RDFa [RDFa10] processing, so must not be defined.

#### › 4.2.5 The property Data Type

##### › 4.2.5.1 Syntax

The property data type is a compact means of expressing an IRI [RFC3987] and consists of an optional prefix separated from a reference by a colon.

(EBNF productions ISO/IEC 14977)
property | `=` | [ prefix , ":" ] , reference; |
prefix | `=` | ? xsd:NCName ? ; |
reference | `=` | ? irelative-ref ? ; | /* as defined in [RFC3987] */

The property data type is derived from the CURIE data type defined in [RDFa10], and represents a subset of CURIEs.

The following example shows a property value composed of the prefix `dcterms` and the reference `modified`.

    <meta property="dcterms:modified">2011-01-01T12:00:00Z</meta>

After processing, this property would expand to the following IRI:

    http://purl.org/dc/terms/modified

as the `dcterms:` prefix is a reserved prefix that maps to the IRI `http://purl.org/dc/terms/`.

When a prefix is omitted from the property value, the expressed reference represents a term from the default vocabulary.

The following example shows a property value taken from the default vocabulary.

    <meta … property="role">aut</meta>

This property would expand to:

    http://idpf.org/epub/vocab/package/#role

when the IRI for the default vocabulary is concatenated with the reference.

An empty string does not represent a valid property value, even though it is valid to the definition above.

##### › 4.2.5.2 Processing

A Reading System must use the following rules to create an IRI [RFC3987] from a property:

- If the property consists only of a reference, the IRI is obtained by concatenating the IRI stem associated with the default vocabulary to the reference.

- If the property consists of a prefix and reference, the IRI is obtained by concatenating the IRI stem associated with the prefix to the reference. If no matching prefix has been defined, the property is invalid.

The resulting IRI must be valid to [RFC3987]. Reading Systems are not required to resolve this IRI, however.

### › 4.3 Package Metadata Vocabulary

#### › 4.3.1 Overview

This section is informative

The following sections both define a set of properties for use in package metadata and constitute a referenceable vocabulary. This vocabulary is the default vocabulary reserved by this specification for the use of unprefixed terms in package metadata.

The properties defined in this vocabulary are referenceable using the base IRI `http://idpf.org/epub/vocab/package/#`.

### note

Property usage examples in the following sections have been drawn from the `metadata` and `meta` examples whenever possible. Refer to those examples for fuller context.

#### › 4.3.2 Metadata `meta` Properties

The `meta` element properties enhance Publication metadata by providing additional level(s) of detail.

These properties must reference the expression or resource they augment in the `refines` attribute on their parent `meta` element.

The following tables detail the available properties.

`› alternate-script`
Description: | The `alternate-script` property provides an alternate expression of the associated property value in a language and script identified by the `xml:lang` attribute. This property is typically attached to `creator` and `title` properties for internationalization purposes.
Allowed value(s): | `xsd:string`
Cardinality: | In the metadata section: `zero or more` Attached to other metadata: `zero or one`
Extends: | All properties.
Example: | `<meta refines="#creator" property="alternate-script" xml:lang="ja">村上 春樹</meta>`

`› display-seq`
Description: | The `display-seq` property indicates the numeric position in which to display the current property relative to identical metadata properties (e.g., to indicate the order in which to render multiple `title`s). When the `display-seq` property is attached to some, but not all, of the members in a set, only the elements identified as having a sequence should be included in any rendering.
Allowed value(s): | `xsd:unsignedInt`
Cardinality: | In the metadata section: `zero or more` Attached to other metadata: `zero or one`
Extends: | All properties.
Example: | `<meta refines="#t2" property="display-seq">1</meta>`

`› file-as`
Description: | The `file-as` property provides the normalized form of the associated property for sorting.
Allowed value(s): | `xsd:string`
Cardinality: | In the metadata section: `zero or more` Attached to other metadata: `zero or one`
Extends: | All properties.
Example: | `<meta refines="#creator" property="file-as">Murakami, Haruki</meta>`

`› group-position`
Description: | The `group-position` property indicates the numeric position in which the Publication is ordered relative to other works belonging to the same group (whether all EPUBs or not). The `group-position` property can be attached to any metadata property that establishes the group (such as a series title). A Publication can belong to more than one group.
Allowed value(s): | A single `xsd:unsignedInt` or series of decimal-separated numbers (e.g., `1` or `2.2.1`).
Cardinality: | In the metadata section: `zero or more` Attached to other metadata: `zero or one`
Extends: | All properties.
Example: | `<meta refines="#t3" property="group-position">2</meta>`

`› identifier-type`
Description: | The `identifier-type` property indicates the form or nature of an `identifier`. When the `identifier-type` value is drawn from a code list or other formal enumeration, the `scheme` attribute should be attached to identify its source.
Allowed value(s): | `xsd:string`
Extends: | `identifier`
Cardinality: | In the metadata section: `zero or more` Attached to other metadata: `zero or one`
Example: | `<meta refines="#src-id" property="identifier-type" scheme="onix:codelist5">15</meta>`

`› meta-auth`
Description: | The `meta-auth` property provides the name of a party or authority responsible for an instance of package metadata.
Allowed value(s): | `xsd:string`
Cardinality: | In the metadata section: `zero or more` Attached to other metadata: `zero or one`
Extends: | All properties.
Example: | `<meta refines="isbn-id" property="meta-auth" id="meta-authority-01">Metadata Authority Inc.</meta>`

`› role`
Description: | The `role` property describes the nature of work performed by a `creator` or `contributor` (e.g., that the person is the author or editor of a work). When the `role` value is drawn from a code list or other formal enumeration, the `scheme` attribute should be attached to identify its source.
Allowed value(s): | `xsd:string`
Cardinality: | In the metadata section: `zero or more` Attached to other metadata: `zero or one`
Extends: | `contributor`, `creator`
Example: | `<meta refines="#creator" property="role" scheme="marc:relators">aut</meta>`

`› title-type`
Description: | The `title-type` property indicates the form or nature of a `title`. When the `title-type` value is drawn from a code list or other formal enumeration, the `scheme` attribute should be attached to identify its source. When a scheme is not specified, Reading Systems should recognize the following title type values: `main`, `subtitle`, `short`, `collection`, `edition` and `expanded`.
Allowed value(s): | `xsd:string`
Extends: | `title`
Cardinality: | In the metadata section: `zero or more` Attached to other metadata: `zero or one`
Example: | `<meta refines="#title" property="title-type">main</meta>`

#### › 4.3.3 Metadata `link` Properties

The following tables define properties for use in the `metadata` `link` element `rel` attribute.

`› marc21xml-record`
Description: | The `marc21xml-record` property indicates the referenced resource is a MARC21 record [MARC21XML].
Cardinality: | `Zero or one`
Extends: | Only applies to the Publication. Must not be used when the `refines` attribute is present.
Example: | `<link rel="marc21xml-record" href="pub/meta/nor-wood-marc21.xml"/>`

`› mods-record`
Description: | The `mods-record` property indicates the referenced resource is a MODS record [MODS].
Cardinality: | `Zero or one`
Extends: | Only applies to the Publication. Must not be used when the `refines` attribute is present.
Example: | `<link rel="mods-record" href="pub/meta/nor-wood-mods.xml"/>`

`› onix-record`
Description: | The `onix-record` property indicates the referenced resource is an ONIX record [ONIX].
Cardinality: | `Zero or one`
Extends: | Only applies to the Publication. Must not be used when the `refines` attribute is present.
Example: | `<link rel="onix-record" href="pub/meta/nor-wood-onix.xml"/>`

`› xml-signature`
Description: | The `xml-signature` property indicates the referenced resource contains an XML Signature [XML DSIG Core] for the Publication or associated property. The `link` element's `href` attribute typically references a specific `signature` element in the Signatures.xml file [OCF3] via a fragment identifier.
Cardinality: | `Zero or more`
Extends: | All properties.
Example: | `<link refines="#meta-authority-01" rel="xml-signature" href="../META-INF/signatures.xml#MAI-Signature"/>`

`› xmp-record`
Description: | The `xmp-record` property indicates the referenced resource is an XMP record [XMP].
Cardinality: | `Zero or one`
Extends: | Only applies to the Publication. Must not be used when the `refines` attribute is present.
Example: | `<link rel="xmp-record" href="pub/meta/nor-wood-xmp.xml"/>`

#### › 4.3.4 Manifest `item` Properties

The following tables define properties for use in the `manifest` `item` element `properties` attribute.

The `Applies to` field indicates which Publication Resource type(s) the given property may be specified on, the `Cardinality` field indicates the number of times the property must appear within the Package Document scope, and the `Usage` field indicates usage conditions.

`› cover-image`
Description: | The `cover-image` property identifies the described Publication Resource as the cover image for the Publication.
Applies to: | All raster and vector image types
Cardinality: | `Zero or one`
Usage: | Optional.

`› mathml`
Description: | The `mathml` property indicates that the described Publication Resource contains one or more instances of MathML markup.
Applies to: | EPUB Content Documents
Cardinality: | `Zero or more`
Usage: | Must be set if and only if the criterion specified in `Description` above is met.

`› nav`
Description: | The `nav` property indicates that the described Publication Resource constitutes the EPUB Navigation Document of the Publication.
Applies to: | The EPUB Navigation Document
Cardinality: | `Exactly one`
Usage: | Required.

`› remote-resources`
Description: | The `remote-resources` property indicates that the described Publication Resource contains one or more internal references to other Publication Resources that are located outside of the EPUB Container. (refer to Publication Resource Locations for more information).
Applies to: | All Publication Resources with the capability of internal referencing (e.g., XHTML Content Documents, SVG Content Documents, EPUB Style Sheets and Media Overlay Documents).
Cardinality: | `Zero or more`
Usage: | Must be set if and only if the criterion specified in `Description` above is met.

`› scripted`
Description: | The `scripted` property indicates that the described Publication Resource is a Scripted Content Document (i.e., contains scripted content and/or elements from `HTML5 forms`).
Applies to: | EPUB Content Documents
Cardinality: | `Zero or more`
Usage: | Must be set if and only if the criterion specified in `Description` above is met.

`› svg`
Description: | The `svg` property indicates that the described Publication Resource contains one or more instances of SVG markup.
Applies to: | XHTML Content Documents; the value is implied for SVG Content Documents.
Cardinality: | `Zero or more`
Usage: | Must be set if and only if the criterion specified in `Description` above is met.

`› switch`
Description: | The `switch` property indicates that the described Publication Resource contains one or more instances of the `epub:switch` element.
Applies to: | XHTML Content Documents.
Cardinality: | `Zero or more`
Usage: | Must be set if and only if the criterion specified in `Description` above is met.

The `mathml`, `remote-resources`, `scripted`, `svg` and `switch` properties must be specified whenever the resource referenced by an `item` matches their respective definitions. These properties do not apply recursively to content included into a resource (e.g., via the HTML5 `iframe` element). For example, if a non-scripted XHTML Content Document embeds a scripted Content Document, only the embedded document's manifest `item` `properties` attribute will have the `scripted` value.

Examples

The following example shows a `manifest` `item` element that represents the cover image of a Publication.

    <item properties="cover-image" id="ci" href="cover.svg" media-type="image/svg+xml" />

The following example shows a `manifest` `item` element representing a Scripted Content Document that also contains embedded `MathML`.

    <item properties="scripted mathml" id="c2" href="c2.xhtml" media-type="application/xhtml+xml" />

#### › 4.3.5 Spine `itemref` Properties

The following tables define properties for use in the `itemref` element `properties` attribute.

The `Cardinality` field indicates the number of times the property must appear within the Package Document scope, and the `Usage` field indicates usage conditions.

`› page-spread-left`
Description: | The `page-spread-left` property indicates that the first page of the associated `item`'s EPUB Content Document represents the left-hand side of a two-page spread.
Cardinality: | `Zero or more`
Usage: | Optional. This property must not be specified on an `itemref` that also specifies the `page-spread-right` property.

`› page-spread-right`
Description: | The `page-spread-right` property indicates that the first page of the associated `item`'s EPUB Content Document represents the right-hand side of a two-page spread.
Cardinality: | `Zero or more`
Usage: | Optional. This property must not be specified on an `itemref` that also specifies the `page-spread-left` property.

Examples

The following example shows how a two-page spread of a map might be indicated in the `spine`.

    <spine>
    	<itemref idref="title"/>
    	<itemref idref="ps-1-l" properties="page-spread-left"/>
    	<itemref idref="ps-1-r" properties="page-spread-right"/>
    	<itemref idref="toc"/>
    	…
    </spine>

## › 5 Publication Resources

### › 5.1 Core Media Types

The following table lists the EPUB 3 Core Media Types. When a Publication Resource conforms to a Core Media Type specification, it is a Core Media Type Resource and can be included in the Publication without the provision of fallbacks (refer to Restrictions and Fallbacks for more information).

The columns in the table represent the following information:

Media Type

  The MIME media type [RFC2046] used to represent the given Publication Resource in the manifest.

Content Type Definition

  The specification to which the given Core Media Type Resource must conform.

Applies to

  The Publication Resource type(s) that the Media Type and Content Type Definition applies to.

EPUB Core Media Types
Media Type | Content Type Definition | Applies to
--- | --- | ---
Image Types
`image/gif` | [GIF] | GIF Images
`image/jpeg` | [JPEG] | JPEG Images
`image/png` | [PNG] | PNG Images
`image/svg+xml` | SVG Content Documents [ContentDocs30] | SVG documents
Application Types
`application/xhtml+xml` | XHTML Content Documents [ContentDocs30] | XHTML Content Documents and the EPUB Navigation Document.
`application/x-dtbncx+xml` | [OPF2] | The superseded NCX
`application/vnd.ms-opentype` | [OpenType] | OpenType fonts
`application/font-woff` | [WOFF] | WOFF fonts
`application/smil+xml` | [MediaOverlays30] | EPUB Media Overlay documents
`application/pls+xml` | [PLS] | Text-to-Speech (TTS) Pronunciation lexicons
Audio Types
`audio/mpeg` | [MP3] | MP3 audio
`audio/mp4` | [AAC LC], [MP4] | AAC LC audio using MP4 container
Text Types
`text/css` | EPUB Style Sheets [ContentDocs30] | EPUB Style Sheets.
`text/javascript` | [RFC4329] | Scripts

### note

This specification does not define any video codecs as Core Media Types. Refer to the note in EPUB Publications — Reading System Conformance above for informative recommendations on support for video codecs in EPUB Publications.

### › 5.2 Restrictions and Fallbacks

#### › 5.2.1 Foreign Resource Restrictions

All Publication Resources of an EPUB Publication must be Core Media Type Resources or must provide a Core Media Type fallback. The cases in which Foreign Resource may be used, and the requirement and rules for Core Media Type fallback provision in such cases, are detailed below.

Intrinsic Fallback in EPUB Content Documents

  › Foreign Resources may be referenced from EPUB Content Document elements that have explicit intrinsic fallback mechanisms (e.g., the [HTML5] `object`, `canvas`, `audio` and `video` elements). A Core Media Type resource must be provided via the given element's intrinsic fallback mechanism in such cases.

  › For the [HTML5] `video` element, the image referenced by the `poster` attribute and text content embedded within the `video` element are also considered valid Core Media Type fallbacks in addition to the `video` element's intrinsic fallback capabilities. For the purpose of providing a last resort fallback for Reading Systems that do not support video or the given video format(s), at least one of these should be included with each occurrence of the `video` element.

  › For the [HTML5] `audio` element, text content embedded within the element is also considered a valid Core Media Type fallback in addition to the `audio` element's intrinsic fallback capabilities. For the purpose of providing a last resort fallback for Reading Systems that do not support audio, embedded text content should be included with each occurrence of the `audio` element.

  › In this version of this specification, the [HTML5] `track` element is exempt from the Core Media Type usage rule: Foreign Resources may be referenced from `track` without the provision of a Core Media Type fallback.

Intrinsic Fallback in EPUB Style Sheets

  › Fonts embedded in Content Documents or EPUB Style Sheets using the `@font-face` mechanism may be Foreign Resources. Reading Systems must use the rules for matching font styles [CSS3Fonts] when identifying a fallback for an unsupported font type.

Spine Resources

  › Foreign Resources may be referenced directly from spine `itemref` elements, and in this case Manifest fallbacks must be provided.

#### › 5.2.2 Manifest Fallbacks

Fallbacks must be provided for each Publication Resource referenced in a spine `itemref` element that is not an EPUB Content Document.

Fallbacks are provided using the `fallback` attribute on the manifest `item` element that represents the Publication Resource. The `fallback` attribute's IDREF [XML] value must resolve to another `item` in the `manifest`. This fallback `item` may itself specify another fallback `item`, and so on.

The ordered list of all the ID references that can be reached starting from a given item's `fallback` attribute represents the fallback chain for that item. The order of the resources in the fallback chain represents the Authors' preferred fallback order.

A Reading System that does not support the Media Type of a given Publication Resource must traverse the fallback chain until it has identified at least one supported Publication Resource to be used in place of the unsupported resource. If the Reading System supports multiple Publication Resources in the fallback chain, it may select the resource to use based on specific properties of that resource, otherwise it should honor the Authors' preferred fallback order.

A fallback chain must contain at least one EPUB Content Document and must not contain any circular- or self-references to `item`s in the chain.

Fallbacks may also be provided for Top-level Content Documents that are EPUB Content Documents; a Reading System may choose to utilize such fallbacks in order to find the optimal version of a Content Document to render in a given context. An example of when this feature can be utilized is when providing fallbacks for scripted content [ContentDocs30].

### › 5.3 Publication Resource Locations

All Publication Resources must be located in the EPUB Container, with the following exceptions:

- › Audio resources may be located in the Container or remotely.

- › Video resources may be located in the Container or remotely.

Authors should prefer locating audio and video resources in the Container to allow the user access to the entire presentation regardless of connectivity status.

### note

The above rules for Publication Resource locations apply regardless of whether the given resource is a Core Media Type Resource or a Foreign Resource.

### note

The inclusion of remote resources in an EPUB Publication is indicated via the `remote-resources` property on the manifest `item` element.

### › 5.4 XML Conformance

Any Publication Resource that is an XML-Based Media Type must meet the following constraints:

- › It must be a conformant XML 1.0 Document as defined in Conformance of Documents [XMLNS].

- › External identifiers must not appear in the document type declaration [XML].

- › It must not make use of XInclude [XInclude].

- › It must be encoded in UTF-8 or UTF-16 [Unicode].

The above constraints apply regardless of whether the given Publication Resource is a Core Media Type Resource or a Foreign Resource.

## › Appendix A. Package Document Schema

The schema for Package Documents is available at http://www.idpf.org/epub/30/schema/package-30.nvdl.

This schema is normative.

### note

Validation using this schema will require a processor that supports [NVDL], [RelaxNG] and [ISOSchematron].

Note, however, that the NVDL schema layer can be substituted by a multi-pass validation using the embedded RELAX NG and ISO Schematron schemas alone.

## › Appendix B. The `application/oebps-package+xml` Media Type

This appendix registers the media type `application/oebps-package+xml` for the EPUB Package Document. This registration supersedes [RFC4839].

The Package Document is an XML file that describes an EPUB Publication [Publications30]. It identifies the resources in the Publication and provides metadata information. The Package Document and its related standards are maintained and defined by the International Digital Publishing Forum (IDPF).

MIME media type name:

  `application`

MIME subtype name:

  `oebps-package+xml`

Required parameters:

  None.

Optional parameters:

  None.

Encoding considerations:

  Package Documents are UTF-8 or UTF-16 encoded XML.

Security considerations:

  Package Documents contain well-formed XML conforming to the XML 1.0 specification.

  Clearly, it is possible to author malicious files which, for example, contain malformed data. Most XML parsers protect themselves from such attacks by rigorously enforcing conformance.

  All processors that read Package Documents should rigorously check the size and validity of data retrieved.

  There is no current provision in the EPUB Publications 3.0 standard for encryption, signing, or authentication within the Package Document format.

Interoperability considerations:

  None.

Published specification:

  This media type registration is for the EPUB Package Document, as described by the EPUB Publications 3.0 specification located at http://www.idpf.org/epub/30/spec/epub30-publications.html.

  The EPUB Publications 3.0 specification supersedes the Open Packaging Format 2.0.1 specification, which is located at http://idpf.org/epub/20/spec/OPF_2.0.1_draft.htm and which also uses the `application/oepbs-package+xml` media type.

Applications which use this media type:

  This media type is in wide use for the distribution of ebooks in the EPUB format. The following list of applications is not exhaustive.

  - Adobe Digital Editions

  - Aldiko

  - Azardi

  - Apple iBooks

  - Barnes & Noble Nook

  - Calibre

  - Google Books

  - Ibis Reader

  - MobiPocket reader

  - Sony Reader

  - Stanza

Additional information:
  Magic number(s):

    none

  File extension(s):

    `.opf`

  Macintosh File Type Code(s):

    TEXT

  Fragment Identifiers:

    The IDPF maintains a registry of linking schemes at http://idpf.org/epub/linking/. Some of these schemes define custom fragment identifiers that resolve to `application/oebps-package+xml` documents.

Person & email address to contact for further information:

  William McCoy, bmccoy@idpf.org

Intended usage:

  COMMON

Author/Change controller:

  International Digital Publishing Forum (http://www.idpf.org)