When people say the word e-book they don’t always mean the same thing. The distinction among types of e-books is very important when it comes to e-book design.

In the world of big commercial publishing e-books are nearly synonymous with Kindle. (And I’m including related formats such as EPUB in this category.) These e-books are designed for use on dedicated reading devices or other portable devices (e.g., iPhones). The key concept here is re-flow: forget about pages, as in printed books. The e-book is a stream of text that automatically re-shapes itself depending upon the width and length of the screen. And forget about design, at least for now. Currently, designing this type of e-book is all about making the e-book look as decent as possible within the severe limitations of e-book reading devices.

E-books based on re-flow are here to stay. But I’m betting within a few years that the design capabilities for this type of e-book will improve. That will happen in the same way Web design has improved over the years. Or, possibly, perhaps re-flow e-books always will be the bare-bones version of books.

As long as people are happy to buy that format, why should publishers spend the money to make the content formatted any better when there’s always the alternative of PDF and even print for those who want a more typographic experience. The good aspect of all this is that consumers may be able to read books in whatever format they prefer.

Actually, with all the announcements coming out of the Consumer Electronics Show in Las Vegas, the capabilities for better looking e-books may be approaching even more rapidly than I expect. Then again, after working with technology for a couple of decades, I know that real change doesn’t happen as quickly as press releases are spit out by marketing departments.

The other common definition of an e-book is PDF, where what you see on the screen looks like the printed page. This works fine on a decent-sized screen (i.e., desktop, laptop, or even a netbook), but is painfully difficult on a small screen. From a design perspective, PDF offers the most flexibility and is the easiest to produce if you already have the book designed for print.

E-books based on PDF are here to stay.

A variation on the PDF e-book is the screen-oriented PDF: the content is designed to fit the screen and resembles a fantastic PowerPoint presentation more than a book. These screen-oriented PDFs are more like a brochure, usually less than 50 pages, and often given away for free. As with any type of PDF, the screen-oriented PDF offers a lot of options for the designer. Commercial publishing houses are not too interested in this format, but Internet marketers make a lot of requests for it.

Enhanced e-books are yet another category: text-based e-books supplemented with visuals and additional features such as audio or video interviews with the authors and other background information. Commercial publishers seem very interested in enhanced e-books for the value-added features, which in turn can result in a higher price for enhanced e-books. Of course, all that material also simply could exist on a Web site. But how do your charge for a Web site? Hence, back to e-books where there’s an easily recognizable price model for consumers.

And what about e-books and magazines that follow a cloud model? That’s worth exploring in a post all its own.