The code could be better (as could anyone's). There is a strong focus on using local variables instead of global and the naming conventions make following the logic from one function to the next a little difficult. This, however, does not diminish the value of the concepts presented.
To use the book, you "MUST" download the files. Not only are they a lot easier to read, you can comment them extensively as you go and pick up logic bits.
An inportant suggestion is to not blow through the example application too quickly. If you take the time to take them apart, modify them and reassemble, you will pick up much more than just running them reading the code and moving on.
I bought it, used it and would buy it again...