I think this will be a great help as I have previously only concentrated on card magic.
I'm going to take some heat for saying this, but card magic is really overplayed these days and specializing in it and then trying to do mentalism is quite possibly one of the worst ideas you can have.
I would highly recommend getting Bob Cassidy's Fundamentals as well as Principia Mentalia. I normally recommend these before 13 Steps, just because you will feel that th effects are more applicable right now, without having to rework them or "update" them. Don't get me wrong, 13 Steps PMM are both great books and resources for material. However, I think having a better understanding of mentalism will help you study those texts and get the most out of them.
// Daniel