1. All text must be available in a logical reading order

Adapted with permission from EPUB 3 Best Practices (O'Reilly Media) To paraphrase a common expression, there are three things you need to know about a finished EPUB 3 file: it must adhere to rules, rules, and damned rules. Which is only to say that there is nothing unique about EPUB 3 as a document publishing format. The rules are there to ensure that your content can be opened and rendered by any reading system. They can’t tell you how your content will look on any given reading system, but they can alert you to bugs that are the result of bad markup. If you skip the validation stage and assume that just because it seemed to be fine testing in a reading system, or a program exported it so it must be valid, you run the risk of a lot of wasted time and effort later.

Adapted with permission from EPUB 3 Best Practices (O'Reilly Media) An alternative (and complement) to human narration, and the associated costs of creating and distributing it, is speech synthesis—when done right, that is. The mere thought of synthesized speech is enough to make some people cringe, though, because it’s still typically equated with the likes of poor old much-maligned Microsoft Sam and his tinny, often-incomprehensible renderings. Modern high-end voices are getting harder and harder to distinguish as synthesized, however, and the voices on most reading systems and computers are getting progressively more natural sounding and pleasant to the ears for extended listening. The need to be able to synthesize the text of your ebook is always going to be vital to a segment of your readers, especially when human narration is not available. It’s also generally useful to the broader reading demographic.