Golf Book help

I was at a golf lesson yesterday and the pro was talking about a book that he said was excellent for mastering the mental side of the game. I can't remember the name of it or who it was by, but I think I'd recognise it if I heard the name.

The one thing I can remember was him talking about a line of commitment that you cross on approach to the ball. Any ideas?

 Golf is not a game of perfect , by bob rotella springs to mind!