I have a couple of Bob Rotella's books.  But to be totally honest, I haven't read them yet.  The mental side isn't really my issue.  But because I've heard such great things about his books, I do plan to read them.  If reading a book and thinking about things a little differently can help save a couple strokes a round, I'm in!

I would say 'Own Your Game' by Dave Stockton is one of the best mental golf books out there. I would defiantly read it. Hope this helped!

I use the book by Dr. Bob Rotella, who works with tour players. Its called Golf is not a Game of Perfect. 

Look at books from Dr. Morris Pickens, Sports Psychologist to Zach Johnson, Stewart Cink, and many other great players.  Bob Rotella books are also good.