This book is about the worst reference book I have ever purchased. At no point does it give a complete picture of the information it is trying to portray. For example on page 585 in the reference section, it talks about the Process.kill built-in. However, it does not list the signals that one might use use with this command and it does not specify anywhere in the book. It makes no attempt to be complete and much of the data you need to learn a feature such as the syntax for something simple like "if" is spread out in unrelated examples throughout the book. Badly written and incomplete. The only reason it got 1 star is that is the minimum possible rating.