Superlatives abound describing this book. This is a definite 5 star job - incredibly well done.
The author takes a challenging topic and walks the reader through it, starting at the very beginning of the scripting concept while simultaneously avoiding talking baby-talk to experienced developers and avoiding being condescending to those less experienced.
The author's writing is exceptional with an easy-to-read style that gets the information across clearly and concisely. If you have an interest in scripting for your applications (this material can apply to anything you develop not just for games) - this is the book for you.
If you have more than a passing interest in compiler theory and how this whole wonderful thing hangs together - this is the book for you.
As the author quite rightly declares at the very beginning of the book - this stuff isn't easy to get through. He does however do an admirable job as guide and tutor, and if you are willing to put in the work you will draw an immense amount of knowledge from it.
Always be cautious of 5 star reviews (this one included) but I'm afraid in this case I can only unreservedly recommend it.
As a footnote, those concerned about the windows orientation of this series will be pleasantly surprised. The content applies just as nicely to a *nix box as it does to a windows one. In fact the word linux is even mentioned if I remember correctly :-) The first third is not devoted to windows specific information as is normally seen in these books. The CD contains windows apps but the source code is still applicable - code is code after all.