Yesterday I posted my cookbook for using the free EPUB creator Sigil to produce eBooks in the EPUB format. But, why would you want to produce them in EPUB format. Indeed, what is EPUB?
The EPUB (short for electronic publication) format is a free and an open standard for e-books. EPUB is the most widely accepted format for eBooks. The International Digital Publishing Forum (IDPF) is the trade and standards association for the digital publishing industry that developed and maintains the EPUB standard. You can find the official specifications for EPUB documents on the IDPF website.
In essence an EPUB document is a specially constructed zip file with the .EPUB extension. You can reflow the content of an EPUB document into any size display screen, from a phone to a tablet to a desktop monitor. EPUB also allows for the generation of a navigational table of contents.
The content of a book formatted with EPUB is contained in XHTML and CSS files, which may reference images and embedded fonts, and can be encrypted with DRM.
The pages in an EPUB document are written in XHTML which is a special flavor of HTML. The EPUB file also contains a series of XML files that help format the book so that it can be properly read by an eReader.
There are a number of tools that can generate EPUB files for you, either from plain text, from XHTML, from Microsoft Word, or even from Adobe InDesign. The tool I use for creating EPUB eBooks is Sigil. Sigil is a basic WYSIWYG EPUB editor that works for producing basic EPUB eBooks. If you want to go beyond basic, in these early days when EPUB tools are less than perfect, it's a good idea to know what's going on under the hood so that you can go in and make necessary adjustments.
For example, Word doesn't export drop caps, but you can edit the XHTML files by hand to allow them. InDesign doesn't export text wrap with its EPUB documents, but you can set up the files so that a quick edit to the XHTML achieves that aim. Just like working on a Web page, the more you work using any tool to generate EPUB documents, the more you will want to be able to get to the code and be able to tweak it.
Besides the iBooks application that Apple provides for the iPhone, iPod touch and of course the iPad. EPUB is supported by other devices and client applications including the Barnes and Noble Nook, and the Sony Reader. The Amazon Kindle, at the time of this writing, does not support EPUB. EPUB is supported on desktop and laptop computers using Adobe Digital Editions (which is free) and on various platform smart phones including Android and Blackberry using products like Lucidor, Stanza, Ibis Reader, Aldiko and Mobipocket. EPUB can be considered a write once read on (almost) any device eBook format.
A great source for much of this post and recommended reading is Elizabeth Castro's great book, EPUB Straight to the Point: Creating ebooks for the Apple iPad and other ereaders, published by Peachpit Press in both print and electronic editions.