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Book Business May/June 2013 : Page 23

But they don’t always implement everything, or implement things the same way. And because EPUB 3 is designed to be so accommodating, it can be a bit bewildering at first. This com-bination of almost unlimited flexibility and a rapidly evolving ecosystem can create a paralyzing deer-in-the-headlights reac-tion among publishers that prevents them from taking advan-tage of the new EPUB 3 ecosystem. You’re Not In This Alone Fortunately, as support for EPUB 3 has gained momentum, lots of resources have emerged. EPUBCheck ( epubcheck) tells you if your EPUB 3 file has coding mistakes. The free Readium plug-in for Chrome ( lets you view your EPUB 3 files; it has implemented all EPUB 3.0 fea-tures. The Readium software is open-source, which will make it easier for reading systems to implement EPUB 3; there will soon be an open-source Readium SDK ( as well. IDPF, the organization that gov-erns EPUB, has provided a wealth of EPUB 3 samples (code. so you can see how other pub-lishers have done things, and is developing a Compliance Test Suite ( that will test how well reading systems implement each feature of EPUB 3. The BISG publishes an EPUB 3 Support Grid ( what-we-do-12-152-epub-30-support-grid.php) that moni-tors which features of EPUB 3 are currently supported by each reading system. And O’Reilly recently published (in cooperation with the IDPF) EPUB 3 Best Practices (, a clear and comprehensive guide to the spec, with helpful advice on what to do and what not to do to ensure that your EPUBs work well. (This article is largely based on that book, to which I contributed.) More Than a Website in a Box Because EPUB is a single file format (.epub), and because it is fundamentally based on modern Web standards (HTML5, CSS3, and JavaScript), people often think of EPUB 3 as “just a website in a box” that can be viewed offline. Actually, it’s a whole collec-tion of files — content documents, style sheets, fonts, images, me-dia resources, scripts, metadata and more — that is literally zipped up (an .epub is a type of .zip file) for reliable single-file delivery. More importantly, it’s an organized collection of files, governed by a “package file” that documents what the EPUB contains (in the manifest), what a reading system needs to know about the EPUB and everything in it (in the metadata), a default reading order (the spine) and so forth. Still, a publication starts with the content, and true to EPUB 3’s Web-based foundation, EPUB 3 content documents are al-most always XHTML5 files. (XHTML is HTML using the rules of XML; more about that below.) They can also be SVG — a vec-tor-and XML-based image format — but there are few SVG-based reading systems. As those come along, we’ll see SVG ▲ | JUNE 2013 23

Edwards Brothers Malloy

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