The book begins a three chapter introduction about the involved technologies, Ajax basics and maybe even more important the concept of Web 2.0 and its ongoing evolution. When people think about Ajax they often think 'no refreshing', 'cool widgets' and 'flashy stuff', but nobody really thinks about desktop application architecture within the webbrowser. And Frank Zammetti finely points this out.

The chapters following the introduction are about fully working projects (a project per chapter). Every project uses a different Ajax toolkit/library or combines them differently. For example there's a very good introduction project on how to use DWR or Dojo (though Dojo's full capabilities are not used). Frank also goes into the details of the communication between server and client using XML and JSON. At the end of every chapter, he gives you a couple of suggestions for improvement so you can go at it yourself with your newly gained knowledge.

Not all is perfect though; From the project chapters on, Frank just goes into the details of the project but fails to put it in a context; he doesn't for example explain why a certain Ajax webapplication has 'windows' using divs or why/how/if separation of responsibly is needed (like MVC). It's just the way it is and he only explains the mechanisms. I would've liked his opinion, both conceptually and concrete examples of how he thinks an enterprise web application should be implemented (for example DWR is an excellent candidate as Controller in the MVC marshalling between client and web).

On the Java side he goes into details on how to set up the server (web.xml etc.) and how to configure some toolkits in there (like dwr.xml with DWR). Configuration aside, he explains his server-sided application logic for every project. Again, he just goes into technicalities here and leaves the architectural concepts behind them untouched.

All in all a good book to read; to get introduced to many toolkits and gain awareness of what Web 2.0 really means.

I have read some AJAX books and enjoyed them, but they typically concentrate on the client side and coverage of what occurs on the server side, if any, is generally PHP or a smattering of almost anything. But I'm a Java guy. The book I've been looking for would have not only the server side examples in Java, but would also use Java as the basis of discussion on client-server communication and the tools available to ease the whole process.

The examples cover a variety of interesting projects and technologies, but the coverage of CSS, JavaScript, Servlets etc is very light as to be almost non-existent. Some of the sample code has been cut and paste without too much scrutiny, so they are often bloated by useless or even empty javadoc blocks but this is more of a annoyance than a real problem. Appendix B has several pages of useful links, but I would have liked to have seen this as a closing chapter of the topics that didn't warrant complete coverage.

Interestingly, while core AJAX books tend to favour the client action and be light on what happens on the server, this book leans the other way. If you are looking to buy a single book to cover AJAX this will cause you a problem, but now that you are fore-warned if you get the correct combination of client and server AJAX coverage you'll be well served for your future needs.