New diagnosis

My oldest was diagnosed 2 1/2 years ago with ADHD and ODD. I was never very comfortable with that diagnosis, but after 6 or so months, we got a good support system in place for him. Fast forward to now. We recently decided to get a second opinion, or a new evaluation. He was just diagnosed (at 9 1/2) with ADHD, Aspergers disorder, and generalized anxiety. Instead of upset, I am relieved. This diagnosis fits and explains so much. There is a few new things we need to get in place, but for right now what we are doing works.

I do have one question... My 9 year old is extremely bright, the doctor was great and explained everything to him, but I'd really like to get him a book that talks about aspergers and/or anxiety. To give him a better understanding... He does so much better when he is able to read information and process it on his own, and then ask any questions he might have. Any suggestions on a book that might help him? Hes known about the ADHD for awhile now, but today is the first time aspergers or anxiety have been mentioned to him (though it's what we've thought for awhile now).