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The front matter of a book communicates a lot of helpful and important information to readers. But publishers and authors often find themselves wondering how to handle that information in their ebook files. In the current installments of my column here on Digital Book World, I am delving into some best practices, ideas and options for these opening and ending parts of your ebook. In my last installment, we completed our discussion about the copyright page.

Note: As is my standard practice, the markup examples below are all suitable for EPUB 3 files. If you are still creating an EPUB 2 file for some reason, your mileage may vary.

The Nav Doc

In EPUB 2, the Table of Contents (TOC) is actually built into two different files: an HTML file that is visible to the reader as they turn pages through the EPUB, and the NCX file, which is an XML file that most reading systems display as a special navigation option, usually when you select a TOC option from a menu. The reason for using two different files was the need for a TOC that was structurally correct while also having the ability to style the TOC in a way that matches the print book.

In EPUB 3, the needs of these two files have been combined into one: the HTML Nav Doc. The structure of the TOC is achieved by constructing the TOC as an ordered list, and the styling is done in the stylesheet.

As part of this merger, the Nav Doc contains not only the Table of Contents of the book, but also the list of page numbers and additional lists of illustrations, tables, images and more. These were originally included in the NCX, as well, but from what I saw, not many publishers took advantage of them.

The TOC Section

The Table of Contents section is wrapped in a <nav> element that includes the epub:type attribute with a value of “toc“. You can include a heading under that, if desired, before opening the ordered list. Each item in the list should be inside an <a> element that links to the location of that section within the ebook. If the item is just being used for structural purposes, then it can be wrapped in a <span> element instead.

Here is a sample of a TOC section, as seen in The Book of Texas, my sample EPUB 3 file:

<nav id=”toc” epub:type=”toc”>

<h1>Contents</h1>

<ol>

<li><a href=”03-title_page.xhtml”>Title Page</a></li>

<li><a href=”04-copyright.xhtml”>Copyright</a></li>

<li><a href=”05-preface.xhtml”>Preface</a></li>

<li><a href=”07-start.xhtml”>Introduction</a></li>

<li><a href=”08-part1.xhtml”>Part I. The Annals of a State</a>

<ol>

<li><a href=”09-part1_chap1.xhtml”>I. Under Spain and France</a></li>

…

</ol></li>

</ol>

</nav>

The structure of the TOC section, with the items all arranged in nested lists, allows the content to be understood by a software application. What about formatting this section to look nice in an ebook device?

The first step is to remove the default formatting included by all ebook devices and browsers for the ordered list. I do this by adding two styles to the CSS:

nav ol {padding-left: 0;}

nav ol li {display: block;}

The first style removes the default left padding added to the list, and the second switches the default display of the content from list formatting (with the numbers added by the software or browser) to the default “block” display, which is how paragraphs and similar elements display. After that is done, it is not hard to apply whatever design you like to your TOC.

In my next installment, we will continue our discussion about the Table of Contents, with details on how to create the page list and other navigation options. If you have a suggestion for a topic you’d like me to cover—anything related to ebooks or metadata—please post a comment below.

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