The Avid site sells only the first book 101.
https://shop.avid.com/ccrz__ProductD...0I&&store=shop
If you read through the text it says:
"
The second course, Pro Tools 110: Pro Tools Fundamentals II, is available through the extensive network of Avid Learning Partners."
So it looks like that Avid makes a special deal with its training centers, so only they can sell the books (maybe to get a special cut).
I just release the first book for Pro Tools | First called "
Pro Tools | First 12 - How it Works". The book covers everything in great detail and because the free app contains about 80% of the full Pro Tools version, it is a great additional learning tool. Especially it contains graphics and diagrams that are not available in any other books. It is available as pdf, printed book (Amazon), and also available as an interactive multi-touch iBook (Apple's iBooks Store), with a linked 650 term glossary (also with diagrams). You can download a free sample book on the iBOoks Store.
More information on my website.
http://DingDingMusic.com/Manuals
