I read this book over a long weekend. This is not an end-all be-all "do this and your web site will be accessible" instruction book. Rather, it is a book to train you how to think inclusively.
I think it is good for web developers (and possibly designers) who want to ensure their pages and interactive components are accessible. The author goes through several different examples that can be added to any web site (I implemented some on my blog): What should go in a document, a paragraph, a blog post, a menu button, a list of products, a filter widget, and a registration form. As the author goes through examples, he discusses how different choices can affect blind and keyboard users, and those discussions can really be applied to any web page in any situation.
My favorite quote from the book goes something like, "Everybody is a keyboard user when they are eating with their mouse hand."