There are many articles online that will teach you the basics of using AJAX techniques for Web applications but the lack of books on the market to really sink your teeth into are few and far between. I found two this week.
The first book I picked up was titled "Foundations of Ajax", written by Ryan Asleson and Nathaniel T Schutta. The 250 page book covers the basics of AJAX, developer tools, testing and has a great overview of the various AJAX frameworks — an area I knew very little about.
The second book, "Ajax in Action", written by Dave Crane, Eric Pascarello, and Darren James is quite a deal larger at over 600 pages and covers the technology set in more depth. One notable area that is paid a great deal of attention in this book was the section on security. However, I can't decide which is the better book. Both are well written and cover most of the topics that will help you get set up with AJAX. Both books are more than enough to use to gain a solid understanding and will serve as worthy resources. Both are safe investments.
While I've only read these two books, the two books below are also available at the time of writing — no doubt there will be a flood of them in the market soon. I'd be interested to hear from others who have read the books below:
Ajax Patterns and Best Practices by Christian Gross
Professional Ajax by Nicholas C. Zakas, Jeremy McPeak, Joe Fawcett