JavaScript and Ajax go together so what could be more sensible than a book on both topics. The problem is that Ajax is advanced and JavaScript doesn't have to be. While the book does attempt to introduce JavaScript to the complete beginner if you really are struggling with the ideas of programming you might find it all too much.
A task-oriented approach is used which introduces aspects of the language by way of using it to do "real" things. If you find it difficult to see why you should learn about loops, ifs and all the other constructs of a programming language, then you could well benefit from having the need explained. However, you might also find it difficult to see the overall picture of how a programming language works and how it fits together with the other technologies. The explanations start by building a small web application, working with frames, using images, sing forms and so on. The style is also fast paced with lots of box outs, tips and asides. It is well written and not in the least bit condescending or irritating. The tips and additional comments are in the main mostly useful and helpful.
By the time we reach Ajax, however, the book is starting to change a little - the examples are longer and we have the complexity of the server side to worry about. At this point we are moving away from designing dynamic websites into the field of application development and this means real and often complicated programming. After the fundamentals, an Ajax toolkit, the Yahoo! User Interface, is introduced as a way of avoiding many of the practical difficulties and the book rounds off with a look at some additional technologies - jQuery, JSON and bookmarklets to name just a few.
Overall this is a very good book but don't expect it to deliver the impossible and allow you to master all of the technologies current in today's web. If you know a little already and are prepared to read around the subject then this is a comparatively painless way to learn about JavaScript as applied to the web.

<Reviewed in VSJ>