Let me get something straight here: Michael Mahemoff really knows how to teach, this book is one of the most appropriated books for those who want to learn about AJAX and in this review I'll tell you why I think so.
First of all, the book starts explaining all the basics of AJAX with its definitons, how it works, related technologies and more. But the best point is: the author always explains using real-life examples, which makes everything easier to understand. The following chapters cover the AJAX Design Patterns properly. You can think about these design patterns as specific solutions, for example "how to made an auto-complete box with ajax", which will give you a great variety of "what can I do with ajax" things. The book also covers some architectural patterns too.
I think the main goal of this book is not only the great diversity of solutions that you can apply in your projects, but how the author explains them. He always starts the explanation of a design pattern with a brief history of how this pattern can help you giving real examples on where these patterns have being applied. Don't forget that one of the main goals of Design Patterns is to create a "vocabulary" to make an easier reference about a specific subject, and this book completely achieves this goal by giving names for each one of those solutions represented as a Design Pattern.
That's why I believe this book is a "must have" for any AJAX professional or student.

Got this book in late 2006, and just about a month ago, I finished. I was involved in creating web forms using Rich Internet Applications (RIA) early last year, and I was hoping this book would give me some guidance.

Simply put, I did not see what I was hoping to get but there were so many duplicate use-cases, stories which resemble one after another (as some other reviewers did, I did not count how many), but overall the examples were too specific (as an example check this out from CodeExample: Yahoo!Mindset (on page 335)
...
OnClick = "setup('1505998205%3Ac26b16%3A105900fde%3Aff4', 'ajax");
...

I really don't think this statement belongs in a book. In the same story, there is even a mention of Hurricane Katrina. I mean, come on... let's cut the chase. Too many sets of the same "Real-World Examples" used in many different pattern makes the context blurry. It certainly lost me. Yes, it took about 10 months for me to read this book, but I had other projects and priorities.

Overall, the first chapters are well put, explaining what Ajax is etc. But it needs further tuning downstream. I give it 3 out of 5.

This book is not perfect. There are a handful of editing mistakes and the author seems to go out of his way to ignore anything that Microsoft might have created (except ajax of course - wink).

On the positive side, this book is extremely well written. The author has a natural writing style that is conversational but still structured enough to fully cover material. The layout and organization of the book adds to the readability.

It help me clarify the mystery behind AJAX and provided easy to follow examples.

Michael has quickly staked his claim as a major driving force in the world of software design, most notably in the vein of AJAX development, and his outstanding work on "AJAX Design Patterns" is certainly testament to that. Despite the book's title implying a heavy lean towards application development via asynchronous remote scripting, it's actually is more accurate in its subtitle, being applicable towards the trendier Web 2.0 movement (but given the mixed reactions to Web 2.0, I can see how such might want to be played down.)

The book's organization is logically laid out, providing a historical and academic profile of the technological foundations that gave rise to modern-day asynchronous programming. Michael then leads into the actual patterns, being grouped by function. Probably the most relevant to web developers are those related to into the various forms of web remoting, DOM manipulation, and next-gen visualization (i.e., drag-and-drop effects); while programming patterns geared for performance enhancement and code generation will whet the appetites of even the most advanced coders.

(Among my favorite patterns are those dealing with HTTP streaming (a field of which Michael's a pioneer), on-demand JavaScript, and content refreshing.)

If, for no other reason, you buy this book it should be for any developer considering themselves to be cutting-edge should buy this book for the section on Chapter 9 on REST applications development. This in my opinion is the most well-rounded discussion of what RESTful production is(n't), and how to incorporate such architecture into your own web projects. Being a .NET developer, that platform's framework serves to both abstract my kind away from having to directly deal with such concepts, or Microsoft blatantly neglects to mention it at all. After scouring the Web for months looking for good content on REST, Michael lays it all out in easy to understand lingo and examples. I'm having the REST chapter photocopied and bronzed for my desk. It's that good.

The one thing I didn't dig too much about the book is its exclusive lean towards PHP for examples where server-side logic was needed. While other platforms like J2EE, .NET, Ruby on Rails and Cold Fusion are keenly cited for their contributions and capabilities, the vast majority of the code is in PHP. But this is just a personal quirk...I'm obviously not big on PHP.

But that minor preference aside, I've followed this book's development since its days as a wiki. It's an invaluable resource as your online development begins to get more complex in a demanding world expecting web apps with rich UIs and multifaceted formats (e.g., JSON, SOAP, XML, et al.). I find it to serve equally well as programmer's reference and architecture guide. I rarely rate any books a perfect score, but this certainly is deserving of such a nod.

This is truly a masterpiece, and one that no developer doing Web 2.0 work should be without.