The Register has a glowing review of Ajax in Action on their web site.

I haven't had a chance to read the book yet, but I picked it up in Barnes and Noble the other day as it was 20% off and looked good. Looks like I made a good choice. If you are interested in Ajax, this looks like a good intro. Check out your local B&N. The book is probably still on sale and if you have a discount card it will be 30% off. However, feel free to click on the above link instead. :-)