This book is VERY light on content (it's a pretty small book, 193 pages for the primary material). If you just look at the table of contents, you can get more depth in a couple hours of googling.

It just isn't a very useful book. It has nothing to offer a programmer with any level of experience with Linux or embedded systems, and it doesn't really educate the guy who's new to those subjects. It's more like a collection of superficial magazine articles.

The amount of real-time covered is really minimal. It touches on defining real-time computing, then has a (short and fairly useless) chapter on RTAI that doesn't do anything.

Go with Yaghmour's "Building Embedded Linux Systems", it's a MUCH better book, and is probably cheaper.