If you click on the link at the top of the screen, you’ll get more info. You can also buy his book at Barnes & Noble or at Amazon.com. Another book about BL would be The Difinitive Book of Body Language. I’ve seen it mentioned a couple of times on the forum but haven’t read it myself (on my to do list 
) You can also Google the topics, you’ll get a ton of online info. This forum, as well, has a lot of information about both topics. Just do a search.
Hopefully ntk will pop back in here…I know he’s studied BL for quite some time. Maybe he’s got a suggestion or two on where to start your research.