I found this book very useful, and I was able to learn JavaScript from it, although I didn't follow the book's tutorials sequentially.
The most important thing to note is that this book is not really suitable for an experienced programmer who wants to add JavaScript to the list of programming languages that he/she knows. If you already know several other programming languages then you'll find the pace of this book much too slow. There are too many simple examples and too much discussion of basic programming principles.
For a beginning programmer these many examples and down-to-earth discussions are great. The authors assume that the reader has no knowledge of programming at all, which is fine if the reader is new to programming.
A couple of the especially useful things I found in this book were an example showing a clever way of using the onClick event for an "a" tag, and information about where to find the Microsoft script debugger.
On the other hand, I did find a few minor errors. And on page 20 a CD-ROM is mentioned, but in fact no CD-ROM accompanies the book. Instead, as explained on page 5, the sample files from the book are available on the Internet.
So if you're new to programming then this is a good book for you, but if you're an experienced programmer then you should find something else.
Rennie Petersen