I was looking for a book that would give me a better understanding of when and how to use JavaScript in my pages... this wasn't it.
The book has dated badly and now seems "childish" in focus - 130 pages on status bar messages, banners and tickers might have been cool 2 years ago but the Web has moved on.
The book does get two stars though because of a good first chapter on external windows.
The book is an collection of scripts, copied from live Web pages, which the authors discuss and explain. However in some cases their knowledge of the language seems to be lacking and they come out with statements that are just wrong. e.g. (p99) they suggest using an onLoad event handler to warn visitors about riske content on a page before it loads - sounds good except that the onLoad event handler fires AFTER a page has finished loading which completely defeats the purpose of the script.
The authors tell you what their example code does in great detail but not WHY it does it, which would be much more useful for people who want to gain an understanding of the language so they can progress to writing their own scripts.
If you want to learn JavaScript go for the much more practical, clear and authorative 'JavaScript Bible' by Danny Goodman. It is written as less of a cookbook but is still packed with practical code examples which are explained in the context of the language as a whole, rather than in isolation.