EPUB is an e-book file format that uses the ".epub" file extension. The term is short for electronic publication and is sometimes styled ePub. EPUB is supported by many e-readers, and compatible software is available for most smartphones, tablets, and computers. EPUB is a technical standard published by the International Digital Publishing Forum (IDPF). It became an official standard of the IDPF in September 2007, superseding the older Open eBook (OEB) standard.
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. Furthermore, the package node must have the unique-identifier attribute. The .opf file's mimetype is application/oebps-package+xml.
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.
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.
EPUB 3.2 was announced in 2018, and the final specification was released in 2019. A notable change is the removal of a specialized subset of CSS, enabling the use of non-epub-prefixed properties. The references to HTML and SVG standards are also updated to "newest version available", as opposed to a fixed version in time.
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.
The first file in the archive must be the mimetype file. It must be unencrypted and uncompressed so that non-ZIP utilities can read the mimetype. The mimetype file must be an ASCII file that contains the string "application/epub+zip". This file provides a more reliable way for applications to identify the mimetype of the file than just the .epub extension.
EPUB continued to evolve over the years, and in 2016 the IDPF merged with World Wide Web Consortium (W3C) in an attempt to bring the publishing industry inline with the latest in web development. The current version of the EPUB format (3.2) was released in May of 2019, and offers features such as the ability for Internet-connected devices to load fonts and other content from outside the container file itself.
I spent a lot of time in hospital during Covid-19 and being an avid reader I latched on to Kindle on a laptop. The only problem was the free offerings were crap. Later I found Open Library which is a free library online, though they periodically ask for donations. They appear to be limited to discarded library books which they can lend. The quality of the authors is much better though the scanning is variable. Diagrams and pictures are pretty poor.
Adobe Digital Editions uses .epub format for its e-books, with digital rights management (DRM) protection provided through their proprietary ADEPT mechanism. The ADEPT framework and scripts have been reverse-engineered to circumvent this DRM system.
The Amazon Kindle can read unprotected .mobi files, as can Amazon's Kindle application for Windows and MacOS. Amazon has also developed an .epub to .mobi converter called KindleGen, and it supports IDPF 1.0 and IDPF 2.0 EPUB format.
The first e-books in history were in plain text (.txt) format, supplied for free by the Project Gutenberg community, but the format itself existed before the e-book era. The plain text format doesn't support digital rights management (DRM) or formatting options (such as different fonts, graphics or colors), but it has excellent portability as it is the simplest e-book encoding possible as a plain text file contains only ASCII or Unicode text (text files with UTF-8 or UTF-16 encoding are also popular for languages other than English). Almost all operating systems can read ASCII text files (e.g. Unix, Macintosh, Microsoft Windows, DOS and other systems) and newer operating systems support Unicode text files as well. The only potential for portability problems of ASCII text files is that operating systems differ in their preferred line ending convention and their interpretation of values outside the ASCII range (their character encoding). Conversion of files from one to another line-ending convention is easy with free software. DOS and Windows uses CRLF, Unix and Apple's OS X use LF, Mac OS up to and including OS 9 uses CR. By convention, lines are often broken to fit into 80 characters, a legacy of older terminals and consoles. Alternately, each paragraph may be a single line.
When Unicode is not in use, the size in bytes of a text file is simply the number of characters, including spaces, and with a new line counting for 1 or 2. For example, the Bible, which is approximately 800,000 words, is about 4 MB.
But Jordan James shows up with her contractors, builders, and noisy equipment. Her adventure park will take up most of the idyllic region, turning the serenity Calliope treasures into a haven for adrenaline junkies.
This document provides delivery information for all accepted media and files for Apple Books. It describes the basics of EPUB 3 creation, and provides guidelines for various EPUB styles and features. In addition to this guide, two example EPUB files are available for your reference in the Preparing Your Books section in Resources and Help; one is for Flowing books (Apple Books EPUB Example) and the other is for Fixed Layout books (Apple Books Fixed Layout EPUB Example).
Apple Books supports two book types: EPUB (.epub) which can be created with Pages or other third-party tools and Multi-Touch (.ibooks) that can be created using the application iBooks Author. EPUB can be used to create Flowing books and Fixed Layout books.
Nonlinear content (linear="no") includes documents that supplement the main content, but are outside the reading flow of the book. For example, nonlinear content can be charts, tables, review answers, and so on. See Nonlinear Content for more information.
Elements in the Navigation Document are created using the HTML5 element. Because each navigation feature is created using the same element structure, you must also include an epub:type attribute to identify the purpose of each nav structure. The Navigation Document is also a content document and therefore can be visible in the pages of the book.
The main Table of Contents in Apple Books is created using a nav element with an epub:type value of "toc". Readers use the Table of Contents to navigate to key locations in the book. Note that you do not define page numbers for each entry. Apple Books calculates those for the reader to accommodate different font and screen sizes.
The Landmarks structure identifies key component files within the book, such as the cover page, bibliography, and so on. It is created using a nav element with an epub:type value of "landmarks". The Landmarks navigation structure replaces EPUB 2's element. Apple Books references the Landmarks when cutting the sample for a book. A Landmarks nav is required for Fixed Layout books if you do not provide a custom sample.
Landmarks can also be used to define the start page of a Flowing book, which is the first page a reader will see the first time they open a book. Apple Books opens to the first landmark item that contains the epub:type value of "ibooks:reader-start-page". If that value is not specified in the Landmarks navigation structure, Apple Books opens to the first spine item that contains one of the following epub:type landmarks values:
The Landmarks structure uses the epub:type attribute to identify both the element and the document functions listed within it. Apple recommends you identify all of the key files in your book. The required epub:type attribute describes the publication component referenced by the href attribute. The value for the epub:type attribute is case-sensitive. Apple suggests you label the first chapter of the book with an epub:type value of "bodymatter", with all other epub:type attributes tagged with the appropriate type ("toc", "titlepage", "epilogue", "preface", and so on). Within the Landmarks block, there can be only one epub:type attribute of each type; for example, there cannot be multiple epub:type attributes of type "bodymatter". For a full listing of the values available for epub:type, see -vocabs/structure/.
The element using the epub:type="page-list" attribute provides a method to designate pages in an EPUB that correspond to the pages of the physical book. This is especially useful in a classroom setting when the teacher instructs students to turn to a particular page. You can use the optional epub:type="page-list" attribute to define an empty string to that page so that it is not numbered. Similarly, you can define Roman numerals (i, ii, iii), letters (a, b, c), or numbers (1, 2, 3) for page numbers. If you use something other than numbers or a single word, make sure it is meaningful, keep it very short, and check to make sure it doesn't get truncated on the screen.
Apple Books also supports both vertical and horizontal text directions using the CSS 3 Writing Modes as outlined in the EPUB 3 standard. Text direction (horizontal and vertical) is defined by the CSS writing-mode property. The writing-mode must be set on the or element instead of setting it on a descendent element. Supported values include: horizontal-tb (horizontal top-to-bottom), vertical-rl (vertical right-to-left), and vertical-lr (vertical left-to-right). Each content document can support a single writing-mode value. If you want both horizontal and vertical text in your book, then each text direction must be split into separate content documents. 2b1af7f3a8