I've been looking at ajax for quite sometime now.I have read many web site introducing the technology, but this book brings a good formal introduction.Everything you need to know on the basics of Ajax is here.It also introduce several Ajax framework.

I really liked how they show me how to make a Google map wannabe, it helped me get a concrete look at the technology.

I think it's a good book for anyone with limited knowledge in web development.I've mostly been on working on compiled platform application, and Web tech has always been a small hobby, but Ajax really does give an opportunity to bridge the gap, fill the missing link.