Electronic Publication (EPUB)
Filename extension .epub
Internet media type application/epub+zip
Developed by International Digital Publishing Forum (IDPF)
Initial release September 2007
Latest release
(June 26, 2014[1])
Type of format e-book file format
Contained by OEBPS Container Format (OCF) (ZIP)
Extended from Open eBook, XHTML, CSS, DTBook
Standard ISO/IEC TS 30135
Open format? Yes
Website IDPF Home Page

EPUB (short for electronic publication) is a free and open e-book standard by the International Digital Publishing Forum (IDPF). Files have the extension .epub.

EPUB is designed for reflowable content, meaning that an EPUB reader can optimize text for a particular display device. EPUB also supports fixed-layout content. The format is intended as a single format that publishers and conversion houses can use in-house, as well as for distribution and sale. It supersedes the Open eBook standard.[2]


EPUB became an official standard of the IDPF in September 2007, superseding the older Open eBook standard.[3]

In August 2009, the IDPF announced that they would begin work on maintenance tasks of the EPUB standard.[4] Two broad objectives were defined by this working group: "One set of activities governs maintenance of the current EPUB Standards (i.e. OCF, OPF, and OPS), while another set of activities addresses the need to keep the Standards current and up-to-date." The working group expected to be active through 2010, publishing updated standards throughout its lifetime.[5] On April 6, 2010, it was announced that this working group would complete their update in April 2010. The result was to be a minor revision to EPUB 2.0.1 that "...corrects errors and inconsistencies and does not change functionality."[6] On July 2, 2010, drafts of the version 2.0.1 standards appeared on the IDPF website.

On April 6, 2010, it was announced that a working group would form to revise the EPUB specification.[6] In the working group's charter draft, 14 main problems with EPUB are identified, which the group will address. The group was chartered through May 2011, and was scheduled to submit a final draft on May 15, 2011.[7] An initial Editors Draft for EPUB3 was published on November 12, 2010,[8] and the first public draft was published on February 15, 2011.[9] On May 23, 2011, the IDPF released its proposed specification for final review. On October 10, 2011, the IDPF announced that its membership had approved EPUB 3 as a final Recommended Specification.[10]

In September 2012, ISO/IEC JTC1/SC34 re-established Ad Hoc Group 4 on EPUB of IDPF to prepare the creation of a Joint Working Group (JWG) for EPUB. EPUB 3 will be submitted as a Draft Technical Specification by the Korean National Body via the JTC 1 fast-track procedure and it will be assigned to the SC 34/JWG when approved.[11] In November 2014, EPUB3 was publised under the formal name ISO/IEC TS 30135 - Information technology - Digital publishing - EPUB3.[12]

ISO/IEC TS 30135 - Information technology - Digital publishing - EPUB3
Part Number First public release date (first edition) Title Description
Part 1 ISO/IEC TS 30135-1 2014-11-05 EPUB3 Overview
Part 2 ISO/IEC TS 30135-2 2014-11-05 Publications
Part 3 ISO/IEC TS 30135-3 2014-11-05 Content Documents
Part 4 ISO/IEC TS 30135-4 2014-11-05 Open Container Format
Part 5 ISO/IEC TS 30135-5 2014-11-05 Media Overlay
Part 6 ISO/IEC TS 30135-6 2014-11-05 EPUB Canonical Fragment Identifier
Part 7 ISO/IEC TS 30135-7 2014-11-05 EPUB3 Fixed-Layout Documents


  • Free and open
  • Reflowable (word wrap) and resizable text or fixed layout (FXL)[13]
  • Inline raster and vector images
  • Embedded metadata
  • DRM support
  • CSS styling
  • Support for alternative renditions in the same file
  • Use of out-of-line and inline XML islands to extend the functionality of EPUB
  • Support for Audio and Video content (dependent on device support).

File format

Version 3.0.1 (current version)

The EPUB 3.0 Recommended Specification was approved on 11 October 2011. (On June 26, 2014 EPUB 3.0.1 was approved as a minor maintenance update to EPUB 3.0.) EPUB 3.0 supersedes the previous release 2.0.1 of EPUB. Detailed descriptions of the differences between 3.0 and 2.0.1 can be found on the IDPF website.

EPUB 3 consists of a set of four specifications:[14]

  • EPUB Publications 3.0, which defines publication-level semantics and overarching conformance requirements for EPUB Publications
  • EPUB Content Documents 3.0, which defines profiles of XHTML, SVG and CSS for use in the context of EPUB Publications
  • EPUB Open Container Format (OCF) 3.0, 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, which defines a format and a processing model for synchronization of text and audio

The EPUB 3.0 format is intended to address the following criticisms:

  • While good for text-centric books, EPUB may be unsuitable for publications that require precise layout or specialized formatting, such as comic books.[15] Also, it has been criticized for trying to solve an already solved problem instead of fixing unsolved problems.[16]
  • A major issue hindering the use of EPUB for most technical publications is the lack of support for equations formatted as MathML. They are currently included as bitmap or SVG images, precluding proper handling by screen readers and interaction with computer algebra systems. Support for MathML is included in the EPUB 3.0 specification.
  • Other criticisms of EPUB are the specification's lack of detail on linking into, between, or within an EPUB book, and its lack of a specification for annotation. Such linking is hindered by the use of a ZIP file as the container for EPUB. Furthermore, it is unclear if it would be better to link by using EPUB's internal structural markup (the OPF specification mentioned above) or directly to files through the ZIP's file structure.[17] The lack of a standardized way to annotate EPUB books could lead to difficulty sharing and transferring annotations and therefore limit the use scenarios of EPUB, particularly in educational settings, because it cannot provide a level of interactivity comparable to the web.[18]

On June 26, 2014, the IDPF published EPUB 3.0.1 as a final Recommended Specification.[19]

Version 2.0.1

EPUB 2.0 was approved in October 2007, with a maintenance update (2.0.1) intended to clarify and correct errata in the specifications being approved in September 2010.[20] EPUB version 2.0.1 consists of three specifications:

  • Open Publication Structure (OPS) 2.0.1, contains the formatting of its content.[21]
  • Open Packaging Format (OPF) 2.0.1, describes the structure of the .epub file in XML.[22]
  • Open Container Format (OCF) 2.0.1, collects all files as a ZIP archive.[23]

EPUB internally uses XHTML or DTBook (an XML standard provided by the DAISY Consortium) to represent the text and structure of the content document, and a subset of CSS to provide layout and formatting. XML is used to create the document manifest, table of contents, and EPUB metadata. Finally, the files are bundled in a zip file as a packaging format.

Open Publication Structure 2.0.1

An EPUB file uses XHTML 1.1 (or DTBook) to construct the content of a book as of version 2.0.1. This is different from previous versions (OEBPS 1.2 and earlier), which used a subset of XHTML. There are, however, a few restrictions on certain elements. The mimetype for XHTML documents in EPUB is application/xhtml+xml.[21] For a table of the required XHTML modules and a description of the restrictions, see Section 2.2 of the specification.

Styling and layout are performed using a subset of CSS 2.0, referred to as OPS Style Sheets. This specialized syntax requires that reading systems support for only a portion of CSS properties and adds a few custom properties. Custom properties include oeb-page-head, oeb-page-foot, and oeb-column-number. Font-embedding can be accomplished using the @font-face property, as well as including the font file in the OPF's manifest (see below). The mimetype for CSS documents in EPUB is text/css.[21] For a table of supported properties and detailed information, see Section 3.0 of the specification.

EPUB also requires that PNG, JPEG, GIF, and SVG images be supported using the mimetypes image/png, image/jpeg, image/gif, image/svg+xml. Other media types are allowed, but creators must include alternative renditions using supported types.[21] For a table of all required mimetypes, see Section 1.3.7 of the specification.

Unicode is required, and content producers must use either UTF-8 or UTF-16 encoding.[21] This is to support international and multilingual books. However, reading systems are not required to provide the fonts necessary to display every unicode character, though they are required to display at least a placeholder for characters that cannot be displayed fully.[21]

An example skeleton of an XHTML file for EPUB looks like this:

    Pride and Prejudice

Open Packaging Format 2.0.1

The OPF specification's purpose is to "...[define] the mechanism by which the various components of an OPS publication are tied together and provides additional structure and semantics to the electronic publication."[22] This is accomplished by two XML files with the extensions .opf and .ncx.

.opf file

The OPF file, traditionally named content.opf, houses the EPUB book's metadata, file manifest, and linear reading order. This file has a root element package and four child elements: metadata, manifest, spine, and guide. All of these except guide are required. Furthermore, the package node must have the unique-identifier attribute. The .opf file's mimetype is application/oebps-package+xml.[22]

The metadata element contains all the metadata information for a particular EPUB file. Three metadata tags are required (though many more are available): title, language, and identifier. title contains the title of the book, language contains the language of the book's contents in RFC 3066 format or its successors, such as the newer RFC 4646 and identifier contains a unique identifier for the book, such as its ISBN or a URL. The identifier's id attribute should equal the unique-identifier attribute from the package element.[22] For a full listing of EPUB metadata, see Section 2.2 of the specification.

The manifest element lists all the files contained in the package. Each file is represented by an item element, and has the attributes id, href, media-type. All XHTML (content documents), stylesheets, images or other media, embedded fonts, and the NCX file should be listed here. Only the .opf file itself, the container.xml, and the mimetype files should not be included.[22] Note that in the example below, an arbitrary media-type is given to the included font file, even though no mimetype exists for fonts.

The spine element lists all the XHTML content documents in their linear reading order. Also, any content document that can be reached through linking or the table of contents must be listed as well. The toc attribute of spine must contain the id of the NCX file listed in the manifest. Each itemref element's idref is set to the id of its respective content document.[22]

The guide element is an optional element for the purpose of identifying fundamental structural components of the book. Each reference element has the attributes type, title, href. Files referenced in href must be listed in the manifest, and are allowed to have an element identifier (e.g. #figures in the example).[22] A list of possible values for type can be found in Section 2.6 of the specification.

An example OPF file:

    Pride and Prejudice
    Jane Austen




.ncx file

The NCX file (Navigation Control file for XML), traditionally named toc.ncx, contains the hierarchical table of contents for the EPUB file. The specification for NCX was developed for Digital Talking Book (DTB), is maintained by the DAISY Consortium, and is not a part of the EPUB specification. The NCX file has a mimetype of application/x-dtbncx+xml.

Of note here is that the values for the docTitle, docAuthor, and meta name="dtb:uid" elements should match their analogs in the OPF file. Also, the meta name="dtb:depth" element is set equal to the depth of the navMap element. navPoint elements can be nested to create a hierarchical table of contents. navLabel's content is the text that appears in the table of contents generated by reading systems that use the .ncx. navPoint's content element points to a content document listed in the manifest and can also include an element identifier (e.g. #section1).[22][24]

A description of certain exceptions to the NCX specification as used in EPUB can be found in Section 2.4.1 of the specification. The complete specification for NCX can be found in Section 8 of the Specifications for the Digital Talking Book.[24]

An example .ncx file:



    Pride and Prejudice

    Austen, Jane

      Chapter 1

Open Container Format 2.0.1

An EPUB file is a group of files that conform to the OPS/OPF standards and are wrapped in a ZIP file.[2] The OCF specifies how to organize these files in the ZIP, and defines two additional files that must be included.

The mimetype file must be a text document in ASCII that contains the string application/epub+zip. It must also be uncompressed, unencrypted, and the first file in the ZIP archive. This file provides a more reliable way for applications to identify the mimetype of the file than just the .epub extension.[23]

Also, there must be a folder named META-INF, which contains the required file container.xml. This XML file points to the file defining the contents of the book. This is the OPF file, though additional alternative rootfile elements are allowed.[23]

Apart from mimetype and META-INF/container.xml, the other files (OPF, NCX, XHTML, CSS and images files) are traditionally put in a directory named OEBPS.

An example file structure:

--ZIP Container--

An example container.xml, given the above file structure:


Digital rights management

An EPUB file can optionally contain DRM as an additional layer, but it is not required by the specifications.[25] In addition, the specification does not name any particular DRM system to use, so publishers can choose a DRM scheme to their liking. However, future versions of EPUB (specifically OCF) may specify a format for DRM.[23]

The EPUB specification does not enforce or suggest a particular DRM scheme. This could affect the level of support for various DRM systems on devices and the portability of purchased e-books. Consequently, such DRM incompatibility may segment the EPUB format along the lines of DRM systems, undermining the advantages of a single standard format and confusing the consumer.[26][27][28][29][30][31]

When present, DRMed EPUB files must contain a file called rights.xml within the META-INF directory at the root level of the ZIP container.[23]


An open source tool called epubcheck exists for validating and detecting errors in the structural markup (OPS, OPF, OCF) as well as the XHTML and image files. The tool can be run from the command line, or used in webapps and applications as a library. A large part of the original work on the tool was done at Adobe Systems.[32]


Software reading systems

The following software can read and display EPUB files:

Reading Systems and Software[2]
Software License Platform DRM formats supported Notes
Adobe Digital Editions Proprietary Windows, Mac OS X Adobe Content Server Requires online activation for ePub files with DRM.
Aldiko Proprietary Android Adobe Content Server Supports ePub for Android devices.
Sumatra PDF GPL[33] Windows Adobe Content Server Supports ePub for Windows devices.
STDU Viewer Freeware Windows Supports many documents format including ePub.
AZARDI Proprietary Windows, Mac OS X, GNU/Linux, Android, iOS Package Obfuscation Supports ePub 3, ePub 2. Fixed Layout, SMIL, DRM, Online and Mobile versions are available when used with AZARDI:Content Fulfilment Server. No longer maintained.
Bluefire Reader Proprietary iOS, Android Adobe Content Server Supports ePub for Android and iOS devices.
BookGlutton Proprietary Web ? Free online ePub reader focusing on the social aspects of reading. Now closed, but the concept has moved to: http://www.readups.com/ per: http://www.bookglutton.com/
calibre GPL Windows, Mac OS X, GNU/Linux None Primarily for library management, conversion, and transferring to devices, it includes a reader. "Calibre: About". 
FBReader GPL Windows, GNU/Linux, Android, PDAs None
Google Play Books Proprietary Web application, Android, iOS Lektz DRM Supports downloading purchased books as ePub and/or PDF.
iBooks Proprietary Mac OS X, iOS FairPlay[34] Supports EPUB 2 and EPUB 3. Books not readable directly on computers other than Macs.
Lexcycle Stanza Proprietary Windows, Mac OS X, iOS ? Acquired by Amazon in 2009.
Lucifox GPL Windows, Mac OS X, GNU/Linux None Ebook reader add-on with annotations for Firefox. Supports open standard ebooks in EPUB 3- and EPUB 2 format and retrieval of books from OPDS book catalogues.
Mobipocket Proprietary Windows, BlackBerry, Symbian, Windows Mobile None Converts EPUB into .PRC on import.
Okular GPL Windows, Mac OS X, GNU/Linux ?
Snapplify Proprietary All Web Browsers, iOS, Android Adobe Content Server Snapplify SnappSafe DRM Supports downloading purchased books as ePub and/or PDF. Supports PDF, ePUB2 and ePUB3 standard of ebooks.

See also the WorldHeritage category for articles about EPUB readers.

Editing systems

Creation Software
Software Platform License Notes
ABBYY FineReader Windows Commercial Version 11 exports to EPUB format.
Abiword FreeBSD, Linux, Windows GPL Support EPUB 2.0 format export since 2.9.1 release [35]
Adobe InDesign Windows, Mac OS X Commercial Exports to EPUB format. Versions prior to 5.5 create EPUBs that require significant editing to pass ePubCheck or ePubPreFlight. As from InDesign CC 2014, InDesign can export in ePub3 fixed-layout format.
Adobe RoboHelp Windows Unknown Online documentation tool that supports export to EPUB format
Aquafadas Digital Publishing System Windows, Mac OS X Commercial Exports to epub3 Fixed Layout format since version 2.0. The publishing system proposes a rich toolset of enrichments for the InDesign documents. The following subset is preserved during the epub3 export : videos, slideshows, sounds, xhtml snippets, links, actions. The generated epub preserves the layout and styles by embedding the appropriate fonts. It does not require any manual editing to pass the epubcheck test.
Atlantis Word Processor Windows, Portable app Shareware Converts any document to EPUB; supports multilevel TOCs, font embedding, and batch conversion.
BlueGriffon EPUB Edition Windows, Mac OS X, GNU/Linux Commercial Wysiwyg editor. Creates, opens, edits and saves natively EPUB2 and EPUB3 (dated October 2012, only application doing it) formats; does not rely on a proprietary pivot format. Offers full UI-based control on all EPUB2 and EPUB3 metadata. Automatically generates guide and NCX in EPUB3 for compatibility with EPUB2. Includes a complete CSS editor, a SVG editor and a MathML editor. Full support for HTML 5, including video and audio tags, and CSS3.
Booktype Web GPL Book production platform that outputs to many formats, including ePub. The platform can import content in various formats and supports collaborative editing.
calibre Windows, Mac OS X, FreeBSD, GNU/Linux GPL Conversion software and e-book organizer. Allows plugins, including for editing EPUB files; there is for instance a plugin to merge several EPUB files into one.[36]
eLML Windows, Mac OS X, FreeBSD, GNU/Linux Unknown The eLesson Markup Language is a platform-independent XML-based open source framework to create eLearning content. It supports various output formats like SCORM, HTML, PDF and also eBooks based on the ePub format.
Feedbooks Web Unknown Free cloud service for downloading public domain works and for self-publishing.
Help & Manual Windows Commercial Single source publishing tool that generates ePUB amongst several other documentation formats.
HelpNDoc Windows Free for personal use, commercial otherwise. Help authoring tool that generates EPUB files and other formats.
iBooks Author Mac OS X Unknown Desktop publishing and page layout application. Free from Apple. Can export .ibooks format, which is a proprietary format based on EPUB.[37] There are restrictions on the commercial distribution of works created with iBooks in the .ibooks format.[38] These restrictions apply to the .ibooks format only[39] and it can be argued that a file renamed to .epub is not distributed in the .ibooks format.
IGP:Digital Publisher Web Commercial Portal Cloud Service or licence application for digital content publishing to all formats. Generates ePub 2 and ePub 3 fixed and flow layout plus other formats.
iStudio Publisher Mac OS X Commercial Desktop publishing and page layout application.
LibreOffice + eLaix plugin Windows Mac OS X GNU/Linux GPL Text processor with the eLaix plugin can export to ePub3 format. [40]
Lulu.com Web Unknown Converts .doc, .docx, or PDF manuscripts to an ePub in order that they may be sold on the Website in question.
Madcap Flare Windows Commercial Single source publishing tool that can export content as ePUB.
oXygen XML Editor Mac OS X, Windows, FreeBSD, Linux Commercial oXygen XML Editor is the first tool that supports creating, transforming, and validating the documents that comprise the EPUB package.
Pages Mac OS X Unknown Word processor (part of the iWork '09 suite) that can export to EPUB format (Pages '09 only, and only with the iWork 9.0.4 update).
Playwrite Mac OS X Commercial Native EPUB-based word processor. Native to EPUB 3 with EPUB 2 compatibility.
QuarkXPress Mac OS X, Windows Commercial Desktop Publishing Tool, Page Layout Application. Exports also to the ePUB format.
Serif PagePlus Windows Commercial Desktop Publishing Program that can export to the EPUB 2 and EPUB 3 format. Comes with built-in output conversion profiles for targeting specific devices, as well as generic devices. Also includes pre-tested blank eBook templates, or can open and edit existing PDF files and publish as EPUB.
Scrivener Windows, Mac OS X Commercial Program for writers. Includes organization capabilities for fiction writers. Publishes to multiple formats.
Sigil Windows, FreeBSD, GNU/Linux, Mac OS X GPLv3 This application can also open and edit EPUB books, instead of just converting from other formats to EPUB. Since version 0.7, Sigil supports embedding video or audio in EPUB. Development was stopped in February 2014, and was launched again in September 2014 with version 0.8.0 released[41]
eXeLearning Windows, GNU/Linux, Mac OS X GPLv2 This application can be used to create educational interactive web content, HTML5, IMS, SCORM and EPUB3 books[42]

Hardware reading systems

Most dedicated e-book readers support the EPUB format, although the Amazon Kindle line of devices is a notable exception. EPUB reading software is also available for all modern smartphones. Devices that support EPUB include:

See also


  1. ^ "Specifications". IDPF. Retrieved January 25, 2012. 
  2. ^ a b c eBook Technologies, Inc. "EPUB 101". Retrieved 10 July 2014. 
  3. ^ IDPF (Oct 15, 2007). "OPS 2.0 Elevated to Official IDPF Standard". IDPF. 
  4. ^ "IDPF Launches EPUB Standards Maintenance Work". IDPF. August 16, 2009. 
  5. ^ "Charter for EPUB Standards Maintenance WG". IDPF. August 12, 2009. 
  6. ^ a b "Draft Charter for revision to EPUB Standard for IDPF Comment". IDPF. April 6, 2010. 
  7. ^ "EPUB 2.1 Working Group Charter – DRAFT 0.11". IDPF. May 7, 2010. Retrieved June 6, 2010. 
  8. ^ "EPUB3 Working Group". IDPF. November 12, 2010. 
  9. ^ IDPF. "EPUB 3". Retrieved 21 February 2011. 
  10. ^ "EPUB 3". IDPF. Retrieved 8 Dec 2012. 
  11. ^ Resolutions of the ISO/IEC JTC 1/SC 34 Plenary Meeting, Brasilia, Brazil, 2012-06-25, 29, retrieved 2012-10-21, Resolution 8: Re-establishment of Ad Hoc Group 4 on EPUB. SC 34 re-establishes Ad Hoc Group 4 on EPUB of IDPF* with the following terms of reference: – to prepare the creation of a Joint Working Group (JWG) for EPUB (and possibly other related topics) under JTC 1/SC 34 with ISO TC 46 and IEC TC 100 /TA 10 involved. SC 34 notes that EPUB 3 will be submitted as a Draft Technical Specification by the Korean National Body via the JTC 1 fast-track procedure and it will be assigned to the SC 34/JWG when approved. 
  12. ^ ISO, ISO/IEC DTS 30135-1 - Information technology - Digital publishing - EPUB3 -- Part 1: EPUB3 Overview, retrieved 2013-06-05 
  13. ^ Fixed layout is available since version 3.0: http://www.idpf.org/epub/fxl/
  14. ^ EPUB 3 Working Group (11 October 2011). "EPUB 3 Overview Draft". IDPF. Retrieved 11 October 2011. 
  15. ^ Rothman, David (July 27, 2008). "The ePub torture test: Starring ‘Three Shadows,’ a graphic novel". TeleRead: Bring the E-Books Home. 
  16. ^ Fixed Width Layout – A Waste of Time. | A Certain Irreverence
  17. ^ "Links, pointers, bookmarks, highlights: How should .epub do it?". FrontMatters. BookGlutton. March 29, 2008. 
  18. ^ Rothman, David (November 5, 2007). Social annotation and the marketplace of ideas': Time for an IDPF annotation standard for books and other e-pubs!"'". TeleRead: Bring the E-Books Home. 
  19. ^ EPUB 3.0.1 Changes. IDPF. Retrieved on July 8, 2014.
  20. ^ "1.1 EPUB Revision History". IDPF. IDPF. 11 October 2011. 
  21. ^ a b c d e f IDPF (September 4, 2010). "Open Publication Structure (OPS) 2.0.1 – Recommended Specification". IDPF. Retrieved February 21, 2011. 
  22. ^ a b c d e f g h IDPF (September 4, 2010). "Open Packaging Format (OPF) 2.0.1 – Recommended Specification". IDPF. Retrieved February 21, 2011. 
  23. ^ a b c d e IDPF (September 4, 2010). "Open Container Format (OCF) 2.0.1 – Recommended Specification". IDPF. Retrieved February 21, 2011. 
  24. ^ a b "Specifications for the Digital Talking Book". April 21, 2005. 
  25. ^ IDPF (November 20, 2006). "IDPF's Digital Book Standards FAQs". IDPF. 
  26. ^ Gelles, David (January 29, 2010). "Walls close in on e-book garden". Financial Times. 
  27. ^ Rothman, David (August 13, 2009). "Adobe-DRMed ePub isn’t ‘open’: Why the New York Times urgently needs to clarify its Sony eBook Store article". TeleRead: Bring the E-Books Home. 
  28. ^ Biba, Paul (December 21, 2009). "Does the Nook use its own incompatible DRM scheme?". TeleRead: Bring the E-Books Home. 
  29. ^ Biba, Paul (January 28, 2010). "iPad adds to the DRM mess? Apple ebook DRM exclusive to Apple hardware". TeleRead: Bring the E-Books Home. 
  30. ^ Kendrick, James (January 28, 2010). "Who Really Needs an iPad?". jkOnTheRun. 
  31. ^ Dave Dickson (January 27, 2010). "EPUB, iPad and Content Interoperability". Digital Editions. 
  32. ^ "epubcheck: Validation tool for Epub". Google Code. Retrieved January 29, 2010. 
  33. ^ "PDFreaders.org: Removal of SumatraPDF due to inclusion of non-free code". blogs.fsfe.org. Retrieved 2014-06-11. 
  34. ^ Pham, Alex (February 15, 2010). "Apple to wrap digital books in FairPlay copy protection". Los Angeles Times. 
  35. ^ http://www.abisource.com/release-notes/2.9.1.phtml
  36. ^ JimmXinu. "GUI Plugin: EpubMerge". MobileRead Forums. Retrieved 24 February 2012. 
  37. ^ Bott, Ed (January 22, 2012). "How Apple is sabotaging an open standard for digital books". ZDNet. Retrieved January 30, 2012. 
  38. ^ Apple (March 23, 2012). "Apple iBooks Author FAQ". Apple. Retrieved April 26, 2012. 
  39. ^ Apple (March 23, 2012). "Apple iBooks Author FAQ". Apple. Retrieved April 26, 2012. 
  40. ^ http://extensions.libreoffice.org/extension-center/elaix
  41. ^ http://sigildev.blogspot.nl/
  42. ^ http://exelearning.net

External links

  • EPUB 3 Home page Includes links to EPUB Working Group project site and issue tracker.
  • EPUB 2 Maintenance Wiki/Home Page Archive for the maintenance discussions and issue tracking for EPUB development that led to EPUB 2.0.1 approved in 2010 and EPUB 3 in October 2011.
  • EPUB Format Construction Guide (also available in EPUB)
  • Video: Format overview of the .epub file
  • Publisher Tim O'Reilly explains the importance of EPUB
  • Build a digital book with EPUB from IBM developerWorks
  • File Extension EPUB - software that support EPUB files
  • EPUB tooling in the Eclipse project
  • EPUB 3 Support Grid from BISG
  • Build Your First Ebook From Scratch - free online class at Skillshare