As a fan of the Sams "Teach Yourself" books, I was somewhat disappointed in this one. The beauty of the Sams books has always been that you can start at page 1, follow along with the chapters and when you're done with the book, you have a working model and an idea of how you got there. This one hits all the high points, but jumps around and chooses to explain the nuts and bolts first, which struck me as kind of like teaching driver's education by devoting the first half of the class to the internal combustion engine.
Do I know more about Drupal than I did when I started? Definitely. I'm also a lot more scared of it now. I understand that it's a heavy subject and fairly robust, but that's what these books are - or are supposed to be - for.
It gives the basics and may yet turn out to be a good reference, but overall I found it to be an awkward jumping off point for a beginner.