ePub 3.2, Hacker News

(Abstract)

EPUB® 3 defines a distribution and interchange format for digital publications and documents. The EPUB format provides a means of representing, packaging and encoding structured and semantically enhanced Web content – including HTML, CSS, SVG and other resources – for distribution in a single-file container. This specification represents the second major revision of the standard.

EPUB 3 has been widely adopted as the format for digital books (ebooks), and this revision continues to increase the format’s capabilities in order to better support a wider range of publication requirements, including complex layouts, rich media and interactivity, and global typography features. The expectation is that the EPUB 3 format will be utilized for a broad range of content, including books, magazines and educational, professional and scientific publications.

EPUB 3 is modular in nature: it consists of a family of specifications that define the core features and functionality of the standard. This specification represents the primary entry point to standard, but the specifications listed inSpecificationsare all a part of EPUB 3. Anindex to key concepts and definitionsdefined across these specifications is provided at the end of this specification.

The informative [EPUB3Overview] provides a general introduction to EPUB 3. A list of technical changes from the previous revision is also available in the informative [EPUB32Changes].

Status of This Document

This specification was published by the EPUB 3 Community Group. It is not a W3C Standard nor is it on the W3C Standards Track. Please note that under the W3C Community Final Specification Agreement (FSA) other conditions apply. Learn more about W3C Community and Business Groups.

If you wish to make comments regarding this document, please send them to [email protected] (subscribe, archives).

1.Introduction

(1.1) Specifications

The EPUB 3 standard is modular in nature, with core features and functionality defined across a family of sub-specifications.

This specification represents the top-most specification in the family. It includes the conformance requirements for both (EPUB Publications) (the product of the standard) andEPUB Reading Systems(the applications that consume EPUB Publications and present their content to users).

The other specifications that comprise EPUB 3 are as follows:

(EPUB Packages) [Packages32] – defines requirements for eachRenditionof the content.
EPUB Content Documents[ContentDocs32] – defines profiles of XHTML, SVG and CSS for use in the context of EPUB Publications.
EPUB Media Overlays[MediaOverlays32] – defines a format and a processing model for synchronization of text and audio.
EPUB Open Container Format (OCF)[OCF32] – defines a file format and processing model for encapsulating a set of related resources into a single-file (ZIP) (EPUB Container) .
EPUB Accessibility[EPUBAccessibility] – defines accessibility conformance and discovery requirements for

These specifications represent the formal list recognized as belonging to EPUB 3, and that contain functionality referenced as part of the standard. New functionality is also added periodically through the development of extension specifications. Features and functionality defined outside of core revisions to the standard, while not formally recognized in this specification, are nonetheless available for use byAuthorsand Reading System developers.

1.2Organization

This section is non-normative.

This section reviews the organization of the EPUB specifications through the central product they define: the (EPUB Publication) .

An EPUB Publication consists of one or moreRenditionsof its content, each of which is represented by what is called anEPUB Package. An EPUB Package consists of all the resources needed to render the content. The key file among these is thePackage Document, which includes all the metadata used by (Reading Systems) to present the EPUB Publication to the user (e.g., the title and author for display in a bookshelf, as well rendering metadata such as whether content has a fixed layout or can be reflowed). It also provides a complete manifest of resources, and includes aspinethat lists the sequence to render documents in as a user progresses through the content.

An EPUB Package also include another key file called theEPUB Navigation Document. This document provides critical navigation capabilities, such as the table of contents, that allow users to quickly and easily navigate the content.

The requirements for EPUB Packages are defined in [Packages32].

The EPUB Publication’s resources are bundled for distribution in a ZIP-based archive with the file extensionepub. As conformant ZIP archives, EPUB Publications can be unzipped by many software programs, simplifying both their production and consumption.

The container format not only provides a means of determining that the zipped content represents an EPUB Publication (theMimetypefile), but also provides a universally-named directory of informative resources (/ META-INF). Key among these resources is thecontainer.xmlfile, which directs Reading Systems to the available Package Documents.

The container format is defined in [OCF32].

Figure1)

The following example visually represents the structure of the EPUB format.

The structure and containment of an EPUB Publication is only one half of the format, the other half being the content that gets presented to users. This content is built on the Open Web Platform and comes in two flavors:XHTMLandSVG. CalledEPUB Content Documents, these documents typically reference many additional resources required for their proper rendering, such as images, audio and video clips, scripts and style sheets.

Detailed information about the rules and requirements for the production of EPUB Content Documents is provided in [ContentDocs32], and accessibility requirements are defined in [EPUBAccessibility].

Media Overlay Documentscomplement EPUB Content Documents. They provide declarative markup for synchronizing the text in EPUB Content Documents with prerecorded audio. The result is the ability to create a read-aloud experience where text is highlighted as it is narrated. Media Overlay Documents are defined in [MediaOverlays32].

While conceptually simple, an EPUB Publication is more than just a collection of HTML pages and dependent assets in a ZIP package as presented here. Additional information about the primary features and functionality that EPUB Publications provide to enhance the reading experience is available from the referenced specifications, and a more general introduction to the features of EPUB 3 is provided in the informative [EPUB3Overview].

(1.3) Terminology

The following terms are specific to EPUB 3. They are capitalized wherever used.

Only the first instance of a term in a section is linked to its definition.

Author

The person (s) or organization responsible for the creation of anEPUB Publication. The Author is not necessarily the creator of the content.

Content Display Area

The area within the (Viewport) dedicated to the display ofEPUB Content Documents. The Content Display Area excludes any borders, margins, headers, footers or other decoration aEPUB Reading Systemmight inject into the Viewport.

In the case ofsynthetic spreads, the Viewport contains two Content Display Areas.

Core Media Type Resource

A (Publication Resource) that does not require the provision of aFallback(cf . (Foreign Resource) ).

EPUB Container

The ZIP-based packaging and distribution format forEPUB Publicationsdefined in OCF ZIP Container [OCF32].

EPUB Content Document

A (Publication Resource) with an XHTML or SVG media type that contains all or part of the content of an EPUB Publication (i.e., the textual, visual and / or audio content). These resources have to conform to their respectiveXHTMLor (SVG) definitions to be used in the spine or be referenced from another EPUB Content Document.

An EPUB Content Document is a (Core Media Type Resource) , so can be included in theEPUB Publicationwithout the provision offallbacks.

EPUB Navigation Document

A specialization of theXHTML Content Documentthat contains human- and machine-readable global navigation information. The EPUB Navigation Document conforms to the constraints expressed inEPUB Navigation Document[Packages32].

(EPUB Package)

A logical document entity consisting of a set of interrelatedresourcesrepresenting one (Rendition) of anEPUB Publication, as defined by a (Package Document) .

EPUB Publication

A collection of one or more (Renditions) that conform to this specification, packaged in an (EPUB Container) .

An EPUB Publication typically represents a single intellectual or artistic work, but this specification does not circumscribe the nature of the content.

EPUB Reading System(or Reading System)

A system that processesEPUB Publicationsfor presentation to a user in a manner conformant with this specification.

Fixed-Layout Document

AnEPUB Content Documentdirectly referenced from the (spine) that has been designated (pre-paginated) in thePackage Document, as defined inTherendition: layoutProperty[Packages32].

The dimensions to use for rendering Fixed-Layout Documents are defined inFixed Layouts[ContentDocs32].

Foreign Resource

A (Publication Resource) that is not aCore Media Type Resource. Foreign Resources are subject to the fallback requirements defined inForeign Resources.

(Local Resource)

A resource that is located inside the EPUB Container .

Refer toPublication Resource Locationsfor media type specific rules for resource locations.

Manifest

A list of allPublication Resourcesthat constitute the givenRenditionof aEPUB Publication.

Refer to manifest[Packages32] for more information.

Media Overlay Document

An XML document that associates theXHTML Content Documentwith pre- recorded audio narration in order to provide a synchronized playback experience, as defined in [MediaOverlays32].

Package Document

A (Publication Resource) that describes oneRenditionof anEPUB Publication, as defined inPackage Document[Packages32]. The Package Document carries meta information about the Rendition, provides a manifest of resources and defines the default reading order.

Publication Resource

A resource that contains content or instructions that contribute to the logic and rendering of at least one (Rendition) of an (EPUB Publication) . In the absence of this resource, the EPUB Publication might not render as intended by theAuthor. Examples of Publication Resources include a Rendition’s Package Document,EPUB Content Document, CSS Style Sheets, audio, video, images, embedded fonts and scripts.

With the exception of the Package Document itself, the Publication Resources necessary to render a Rendition are listed in that Rendition’s manifest[Packages32] and bundled in The (EPUB Container) file (unless specified otherwise inPublication Resource Locations).

Examples of resources that are not Publication Resources include those identified by the Package Documentlink[Packages32] element and those identified in outbound hyperlinks that resolve to (Remote Resources) (eg, referenced from the (HREF) attribute of an [HTML](a) (element).

Release Identifier

The Release Identifier allows any instance of anEPUB Publicationto be compared against another to determine if they are identical, different versions, or unrelated.

Refer to Release Identifier[Packages32] for more information.

(Remote Resource)

A resource that is located outside of theEPUB Container, typically, but not necessarily, online.

Refer toPublication Resource Locationsfor media type specific rules for resource locations.

(Rendition)

One rendering of the content of anEPUB Publication, as expressed by anEPUB Package.

Scripted Content Document

AnEPUB Content Documentthat includes scripting or an (XHTML Content Document) that contains [HTML]forms.

Refer toScripting[ContentDocs32] for more information.

Spine

An ordered list ofPublication Resources,typically EPUB Content Documents[Packages32], representing the default reading order of the givenRendition of an

Refer to (spine) [Packages32] for more information.

SVG Content Document

AnEPUB Content Documentthat conforms to the constraints expressed inSVG Content Documents[ContentDocs32].

Synthetic Spread

The rendering of two adjacent pages simultaneously on a device screen.

(Text-to-Speech) (TTS)

The rendering of the textual content of anEPUB Publicationas artificial human speech using a synthesized voice.

Top-level Content Document

AnEPUB Content Documentreferenced from thespine, whether directly or via afallback chain[Packages32].

Unique Identifier

The Unique Identifier is the primary identifier for anEPUB Publication, as identified by theunique-identifierattribute [Packages32]. The Unique Identifier can be shared by one or moreRenditionsof the same EPUB Publication.

Significant revision, abridgement, etc. of the content requires a new Unique Identifier.

Viewport

The region of anEPUB Reading Systemin which anEPUB Publicationis rendered visually to a user.

XHTML Content Document

AnEPUB Content Documentthat conforms to the profile of [HTML] defined inXHTML Content Documents[ContentDocs32].

XHTML Content Documents use theXHTML Syntaxdefined in [HTML].

(1.4) Conformance

As well as sections marked as non-normative, all authoring guidelines, diagrams, examples, and notes in this specification are non-normative. Everything else in this specification is normative.

The key words (MAY) ,MUST, (MUST NOT) , (RECOMMENDED) , (SHOULD) , andSHOULD NOT are to be interpreted as described in [RFC2119].

2.Conformance Criteria

(2.1) EPUB Publications

An (EPUB Publication) (MUST) meet all of the following criteria:

It (MUST) include one or moreEPUB Packages, each of which (MUST) conform to the requirements defined in [Packages32].; ItSHOULDconform to the accessibility requirements defined in [EPUBAccessibility].
Publication Resources: (All) **************************************************************************************************************************************************************** (Publication Resources)MUSTadhere to theconstraints for Core Media Type and Foreign Resourcesand be located as perPublication Resource Locations.
Container: It (MUST) be packaged in a (EPUB Container) as defined in [OCF32].

(2.2) ******************************************************************************* EPUB Reading Systems

AnEPUB Reading System(MUST) meet all of the following criteria:

It (MUST) process theEPUB Containeras defined in [OCF32].

(It) MUSTprocessEPUB Packagesas defined in [Packages32].

(It) ***************************************************************************************************************************************************************************************************************************************************** (MAY) support an arbitrary set ofForeign Resource [XInclude] types, and (MUST) process fallbacks for unsupported Foreign Resources as defined inForeign Resources (if not.)

ItSHOULDsupport (remote resources) , as defined inResource Locations.

(It) ***************************************************************************************************************************************************************************************************************************** (MUST) process (XHTML Content Document) as defined inXHTML Content Documents – Reading System Conformance[ContentDocs32].

It (MUST) processSVG Content Documentsas defined inSVG Content Documents – Reading System Conformance[ContentDocs32].

If it has a (Viewport) , it MUST support visual rendering of (XHTML Content Documents) as defined inCSS Style Sheets – Reading System Conformance[ContentDocs32].

If it has a Viewport, it (MUST) support theimage Core Media Type Resources.

If it has the capability to render pre-recorded audio, it (MUST) support the (audio Core Media Type Resources) and (SHOULD) Support Media Overlays [MediaOverlays32].

If it supports (Text-to-Speech) (TTS) rendering, itSHOULDsupport Pronunciation Lexicons [ContentDocs32], [CSS3Speech] andSSML attributes[ContentDocs32] inXHTML Content Documents.

(Note)

It is recommended that Reading Systems support at least one of the H. 264 [H264] and VP8 [RFC6386] video codecs, but this is not a conformance requirement – a Reading System might support other video codecs, or none at all. Authors and Reading System developers need to 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 format, or both.

Accessibility

Backward Compatibility

It (MUST) attempt to process any given rendition of an EPUB Publication whose Package Documentversionattribute is less than ” (3.0) “.

EPUB Publications with older version number s will not always render exactly as intended unless processed according to their respective specifications. Reading SystemsSHOULDsupport such EPUB Publications as defined by those specifications.

Forward Compatibility

It (SHOULD) attempt to process any given Rendition of an EPUB Publication whose Package Documentversionattribute is greater than ” (3.0) “.

XML Processing [EPUBAccessibility]

It (MUST) *********************************************************************************************************************************** (be a) conformant non-validating processor[XML].

(It) MUST be aConformant processoras defined in [XML-NAMES].

(It) ***************************************************************************************************************************************************************************************************************************** (MUST) be a conformant application as defined by [XMLBase].Note: [HTML] and [SVG] are removing support for [XMLBase]. Authors are advised to avoid using this feature.

Note

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

3.Publication Resources

(3.1) ******************************************************************************* (Core Media Types)

(3.1.1) Introduction

EachRenditionof anEPUB Publicationtypically consists of manyPublication Resources. These resources are divided into two categories: those that can be included without fallbacks ( (Core Media Type Resources) ) and those that cannot (Foreign Resources).

Authorsare free to use both types of resources to construct their EPUB Publications, but need to be aware that some Reading Systems might not render the Foreign Resources they use.

As EPUB Publications are designed to be fully consumable on any compliant Reading System, a system of fallbacks is necessary to ensure that the use of Foreign Resources does not impact on the ability of the user to consume the content. This section lists theset of Core Media Type Resourcesand identifiesfallback mechanismsthat can be used to satisfy the consumability requirement.

(3.1.2) Supported Media Types

(Publication Resources) that conform to the following MIME media type [RFC2046] specifications can be included in an EPUB Publication without fallbacks.

The columns in the following table represent the following information:

(Media Type) – The MIME media type [RFC2046] used to represent the given Publication Resource in themanifest[Packages32].

If more than one media type is listed, the first one is the preferred media type. The preferred media type is strongly encouraged for all new EPUB Publications.
(Content Type Definition) – The specification to which the given Core Media Type Resource has to conform.
(Applies to- The Publication Resource type (s) that the Media Type and Content Type Definition applies to.

(3.1.3) Foreign Resources

(Foreign Resources) ***************************************************************************************************************************************************************************************************************************************************** (MAY) be included in an EPUB Publication without a fallback provided they are not referenced fromspineitemrefelements[Packages32] or directly rendered in their native format in EPUB Content Documents (eg, via [HTML] (embedded content) and [SVG]imageandforeignObject(elements).

(Note)

This exception allows Authors to include resources in the EPUB Containerthat are not for use by EPUB Reading Systems. The primary case for this exception is to allow data files to travel with an EPUB Publication, whether for use by scripts in its constituent EPUB Content Documents or for use by external applications (e.g., a scientific journal might include a data set with instructions on how to extract it from the EPUB Container).

When a [XInclude] *********************************************************************************************************************************************** (Foreign Resource) is included in the spine or directly rendered in its native format in an EPUB Content Document, a fallbackCore Media Type Resource [RFC2046] (MUST) be included. Fallbacks take one of the two following forms:

intrinsic fallback mechanisms provided by the format (eg, ability to provide more than one media type or to display an alternate embedded message when a media type cannot be rendered);
manifest fallbacks[Packages32].

Manifest fallbacks are a feature of thePackage Documentthat create fallback chains to Core Media Type Resources. They are used to create fallbacks for Foreign Resources in thespine[Packages32] and when intrinsic fallback capabilities are not available (eg, for the [HTML]img(element).

Refer to the [HTML] and [SVG] specifications for the intrinsic fallback capabilities their elements provide.

(3.2) ******************************************************************************* (Resource Locations)

All (Publication Resources) (MUST) be located in the (EPUB Container) , with the following exceptions:

Audio resourcesMAYbe located outside the EPUB Container.
(Video resources) (MAY) be located outside the EPUB Container.
Resources retrieved by scripts (MAY) be located outside the EPUB Container.
Font resources(MAY) be located outside the EPUB Container.

Note

Authors are encouraged to locate audio, video and script resources inside the EPUB Container whenever feasible to allow users access to the entire presentation regardless of connectivity status.

(3.3) XML Conformance

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

ItMUST (be a conformant XML 1.0 Document as defined inConformance of Documents[XML-NAMES].
External identifiersMUST NOTappear 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 aCore Media Type Resourceor aForeign Resource.

A.Unsupported Features

This specification and its siblings contain certain features that are no longer recommended for use or that are only retained for legacy support reasons. This section defines the meanings of the designations attached to these features and the support expectations for such features.

(A.1) Deprecated Features

Adeprecatedfeature is one that is no longer recommended for use in this version of the specification. Deprecated features typically have had limited or no support in Reading Systems and / or usage in EPUB Publications. If a feature is marked as deprecated, the following hold true:

Authorsare stronglyRECOMMENDEDnot to use the feature in th EIREPUB Publications.
(Reading Systems) (MAY) support the feature.

Note

Developers are advised to consider the unwelcome of encountering content with deprecated features before adding new support for them.

Validation tools (SHOULD) alert Authors that inclusion of the feature is deprecated when encountered in an EPUB Pub

(A.2) Legacy Features

Alegacyfeature is one that is retained only for authoring content that is compatible with versions of EPUB prior to 3.0. If a feature is marked as legacy, the following hold true:

Authors(MAY) include the legacy feature for compatibility purposes.
Reading SystemsMUST NOTsupport the legacy feature in content that conforms to this version of EPUB.

Validation toolsSHOULD NOTalert Authors about the presence of legacy features in anEPUB Publication, as their inclusion is valid for backwards compatibility. Validation tools (MUST) alert Authors if a legacy feature does not conform to its definition or otherwise breaks a usage requirement.

B. (Index)

This section is non-normative.

This index identifies where key concepts are defined in EPUB 3, including element, attribute and property

accessibility[EPUBAccessibility]
Core media type resources
core specifications
CSS style sheets[ContentDocs32]
- (CSS snapshot support)
- prefixed properties
- Reading System overrides
EPUB Navigation Document[Packages32]
- custom nav elements
- hidden attribute
- (landmarks nav element)
- nav element restrictions
- page-list nav element
- toc nav element
fixed layouts[Packages32]
Media Overlays Documents[MediaOverlays32]
- basic playback behaviors
- escapability
- interaction with content documents
- loading
- navigation document playback
- Packaging
  - attaching to content documents
  - metadata
- playback Granularity
- relationship to content documents
- Skippability
- Smil element
  - body element
    - Par element
      - audio element
      - text element
    - seq element
  - (head element)
    - metadata element
- (semantic inflection) (epub: type)
- (structure)
- styling
(OCF abstract container) [OCF32]
(OCF ZIP container) [OCF32]
- encryption
  - (restricted files)
- media type identification(mimetype)
- obfuscation(was font obfuscation)
- ZIP requirements
Package Document[Packages32]
- collection element
- default vocabularies
- fixed layout properties– see alsofixed layouts
- identifiers
- layout properties
  - rendition: align-x-center property
  - rendition: flow property
- metadata element
  - core metadata requirements
  - dc: identifier element
  - (dc: language element)
  - dc: title element
    - importance of order
  - dcterms : modified property(last modified date)
  - Dublin Core optional elements
    - contributors
    - Creators
    - (publication date)
    - publication types
    - subjects
  - link element
  - meta element
- manifest element
  - item element
    - fallbacks
    - media overlay association
    - (media type)
    - properties
    - resource inclusion requirements
- NCX (legacy)
- (package element)
  - prefix declarations
  - (version number)
- property data type
- reserved prefixes
- shared attributes
- spine element
registries
remote resources
scripting[ContentDocs32]
- contexts( container-constrained and spine-level)
- epubReadingSystem object
- (event model)
- security
SVG Content Documents[ContentDocs32]
- (Restrictions)
- Semantic inflection
- SVG version Conformance
Terminology
vocabularies
- Accessibility
- Link
- Manifest Properties
- Media Overlays Metadata
- (Meta Properties)
- Publication Rendering(rendition: properties)
- Spine Properties
- Structural Semantics [EPUBAccessibility]
XHTML Content Documents[ContentDocs32]
- custom attributes
- discouraged constructs( (rp) andEmbed)
- Embedded MathML
- Embedded SVG
  - application of CSS styles
- foreign resource restrictions
- HTML version Conformance
- pronunciation lexicons (PLS)
- (RDFa and microdata) (semantic enrichment)
- semantic inflection
- Speech Synthesis Markup Language (SSML)
  - ssml: ph attribute
  - ssml: alphabet attribute
- (SVG)
- Unicode restrictions
XML conformance

C.Acknowledgements and Contributors

This section is non-normative.

EPUB 3 is developed by the W3C’sEPUB 3 Community Groupin coordination with thePublishing Business Group [Unicode] .

The EPUB 3.2 revision was led by:

Rachel Comerford (Macmillan Higher Education), Chair
Dave Cramer (Hachette Livre), Chair

In addition to the editors, this version of EPUB would not have been possible without significant contributions from:

Aaron Troia
Adam Sobieski
Alberto Pettarin
Andrew Gribben (Houghton Mifflin Harcourt)
Avneesh Singh (DAISY Consortium)
Ben Walters (Microsoft)
Benjamin Young (Wiley)
Bill Kasdorf (BISG)
Brady Duga (Google)
Carlos Araya
Charles LaPierre (Benetech)
Daniel Glazman (Disruptive Innovations) [XMLBase]
Daniel Weck (DAISY Consortium) [XMLBase]
David Herron
Deborah Kaplan
Evan Owens (Cenveo Publisher Services)
Franco Alvarado
Garth Conboy (Google)
Georg Stadler
George Kersher (DAISY Consortium)
Greg Alchin
Hadrien Gardeur (Feedbooks)
Iris Febres
Ivan Herman (W3C)
James Briano [Unicode]
Jeff Buehler
Johan van der Knijff
John Costa (Repub Interactive Technologies LLC)
Julian Calderazi (DigitalBe)
Ken Jones (Circular Software)
Krzysztof Zemczak
Laura Brady
Laurent Le Meur (EDRLab)
Léonie Watson (Paciello Group)
Lloyd Rasmussen (Library of Congress)
Luc Audrain (Hachette Livre)
Makoto Murata (Keio Advanced Publishing Laboratory)
Martin Kraetke (le-tex publishing services GmbH)
Mateus Manço Teixeira (WW Norton)
Matt Curtis [Unicode]
Matt Garrish (DAISY Consortium)
Mike Baker (Houghton Mifflin Harcourt)
Mustapha Lazrek (Microsoft)
N. Erhan Uzumcu
Naomi Kennedy (Penguin Random House)
Nick Ruffilo (VitalSource)
Olaf Hoffmann
Peter Krautzberger (krautzource UG)
Rachel Comerford (Macmillan Higher Education)
Ric Wright [Unicode]
Rick Johnson (VitalSource)
Romain Deltour (DAISY Consortium)
Ruth Tait
Theresa O’Connor (Apple)
Tobias Fischer
Toshiaki Koike (Voyager Japan Inc.)
Tzviya Siegman (Wiley)
Wolfgang Schindler (PONS GmbH) [XMLBase]
Zheng (Jeff) Xu (Rakuten Inc.)

Special thanks go to the former members of the International Digital Publishing Forum, particularly Markus Gylling and Bill McCoy, without whom EPUB would not have become a reality.