Rating: 

The title of the book says all ! This is the defenitive one-and-only book to have if you are serious about JavaScript. If you're not, then you should still have it.

It is precise, plainly written, and extremely accurate.

Macromedia use it as their reference for DreamWeaver and UltraDev references.

I have never encountered a problem that wasn't explained or solutioned in this book.