About 12 years ago I purchased the book 'Mental Management for Great Golf' by Dr. Bee Epstein-Shepherd.
It pretty much blew away the stuff I've read from other books on the mental sde of the golf, giving a lot of *techniques* on mental focus, calming one's self down, and other goodies.
I've forgotten a bit of it since I only read it once and then lost the book in the move, but it was really good. In fact, I use some of the techniques today in order to help lower my high blood pressure.
It's really a book that should be talked about a lot more when it comes to the game.