## Preface

Accessibility is a difficult concept to define. There’s no single magic bullet solution that will make all content accessible to all people. Perhaps that’s a strange way to preface a book on accessible practices, but it’s also a reality you need to be aware of. Accessible practices change, technologies evolve to solve stubborn problems, and the world becomes a more accessible place all the time.

But although there are best practices that everyone should be following, and that will be detailed as we go along, this guide should neither be read as an instrument for accessibility compliance nor as a replacement for existing guidelines.

The goal is to provide you with insights and ideas into how to begin making your publications richer for all readers at the same time that you make them more accessible. Proliferating usability guidelines and muddying the waters of compliance is not its intent. There are areas that would take a book unto themselves to explore in detail in relation to the use of HTML5 content within EPUB, such as the Web Content Accessibility Guidelines (WCAG) and Web Accessibility Initiative’s Accessible Rich Internet Applications (WAI-ARIA). Whenever issues extend beyond what can be covered in these best practices, pointers to where you can obtain more information will be included. Don’t fall into the trap of hand-picking accessibility.

It is also naturally the case with a standard as new and wide-ranging as EPUB 3 that best practices will evolve and develop as the features it offers are explored and implemented. This guide will endeavor to make clear whenever uncertainty exists around an approach, what alternatives there are, and where you should be looking to watch for developments.

You need to be thinking about accessibility and planning good content practices from the outset if you’re going to make the most of the features EPUB 3 has to offer. This guide will be your map, but you have to be willing to follow it.

### Note

This guide is envisioned as a living document and intended to be updated and re-released as new practices and techniques evolve.

## Conventions Used in This Book

The following typographical conventions are used in this book:

Italic

  Indicates new terms, URLs, email addresses, filenames, and file extensions.

`Constant width`

  Used for program listings, as well as within paragraphs to refer to program elements such as variable or function names, databases, data types, environment variables, statements, and keywords.

`Constant width bold`

  Shows commands or other text that should be typed literally by the user.

`Constant width italic`

  Shows text that should be replaced with user-supplied values or by values determined by context.

### Tip

This icon signifies a tip, suggestion, or general note.

### Caution

This icon indicates a warning or caution.