This is clear, concise, and what I would describe as a "page turner" -- you just have to keep reading once you start reading it. It is a basic intro to AJAX, but very solid and detailed. Highest recommendation.

I can't figure out what audience the author intended to write for. There's a chapter that is ostensibly an overview of Javascript, but there is far too little detail for the beginning user. If the target audience was for a non-JS programmer, there's no way they could grab enough of the information presented in the sparse overview and get up and running with any confidence. Conversely, if the user is an intermediate or pro, the JS chapter is superfluous. And that's a huge waste of space in a book that's barely 200 pages including the index.

The author, however, IS very knowledgable and there are some good examples of how to implement Ajax. Just not enough meat on the bones. For a beginning user, there is only enough to get a general sense of what's going on, but not enough to start programming on one's own.

Also, there isn't very much information on "bulletproofing" Ajax as the title indicates. "Bulletproof Web Design" goes to great lengths to show how to bulletproof, but here it's almost an afterthought. Very little info in that regard.

As mentioned, the book is short, and could have used at least another 50 pages to fill in gaps where there is clearly more explanation needed. I've since read "Head First Ajax" which does a better job of getting you up and running.

Normally i don't return books because it's too much trouble for $20 or so. I had to return this one because i could picture the people behind it laughing at me for buying it.

The publisher of this book needs to recall it and take it off the shelf if they want to retain a slim hope of credibility.

The book is devoid of anything useful that you can't find on the wikipedia page on Ajax. When it finally strays from the extremely basic stuff, it fall on its buttocks with all sorts of mistakes.
There are even mistakes that contradict the other mistakes!

Stay far away from this book. it's called "bulletproof" because it's a blackhole of nothingness.

The book is very good will learn you all you need to know to be ajaxian , beginning with Javascript , DOM and Ajax fundamentals for creating bulletproof XHR object , then how to use it with various data ( XML , JSON , HTML ) types and each advantage and disadvantage , then dive into Hijax techniques for accessibility and progressive enhancements and the challenges that will face you during ajax applications developement and how to solve it , and end up with the future of ajax chapter that tell you why and how to choose the right ajax framework for your apps .

This was very interesting. I don't know if its completely bulletproof, but it IS about as bullet resistant as you can make it. He definitely makes good points in every chapter about building and designing your ajax application.
I recommend you read this book when you are learning ajax. For the advanced developer, I would hope you are using these techniques. You should at least read this to make sure you are using similar techniques.
For the self-taught, I would say to definitely read this book. You'll make it through it in a few days of on and off reading. It took me a week of reading on the train (25 minutes each way, so about 5 hours). I'm still thinking about what he said and analyzing it. This tells me he had some excellent ideas.
A recommended Ajax programming book. Don't let page counts fool you. I have some "Bible" books that are awful, BUT they're 1000 pages.
-T-