I have this book, and it's the one that kicked me past the point of wanting to use AJAX and actually doing so... good stuff, a good read, and on-topic. I haven't read it all. I took potshots where I looked for information to get the job done, and even reading that way, it worked!
So go over to Encosia, and follow the instructions to try to win one of the 3 copies Dave is giving away.
The 'first comment' is undoubtedly gone by now, but there's two others up for grabs... trust me, you won't be disappointed with this book!