I was in some large book store a little while ago, and I noticed a book titled something like "How To Use Internet Explorer 5". I pulled it out to skim through it and see how anyone could possibly write a whole book about how to use a GUI web browser. It was one of the largest books there, much larger than many comprehensive books on programming languages.
First... how could anyone write over 800 pages about IE 5!?
And second... the kind of person who would buy a book about IE 5 would definitely never use (or even want to use) any of the detailed features that a book of that length would have to go into.
There must be plenty of computer-illiterate people who want to learn how to use the world wide web well. Either that or some pretty stupid publishers.