I’ve read one of his books, and listened to his tape set. And he’s neither guru nor fraud. He’s simply a motivational speaker. And he’s very, very good at it.
There is a smattering of NLP wackiness and holistic medicine stuff in his material, but very little. Most of his advice is more along the lines of, “Get off your ass and do something.”
For example, on one of his tapes he has a very inspirational story of a friend who was a quadripalegic, but managed to be highly successful and very happy. He contrasted it with stories of several beautiful or talented movie stars who had the world by the tail but were miserable and wound up self-destructing. His point was that happiness is a state of mind, and not necessarily a result of your condition. Whatever your current lot in life, you don’t HAVE to be unhappy. You have control over how you feel about things (chemical imbalances notwithstanding).
Then he gets into a bit of NLP stuff, but it’s along these lines -
"Let’s do an exercise. I want you to stand up. I want you to put a smile on your face. A big grin. Look up at the sky. Smile. Straighten your posture. Swing your arms out, and don’t forget to smile. Now, try to feel bad, but don’t change what you’re doing. Hard, isn’t it?
“Now, sit down. Hang your head. Slouch over. Frown. Now think about something bad. It’s a lot easier, isn’t it? Harder to think happy thoughts, isn’t it?”
His point is that when you’re sad, you send cues to you body to react in a certain way. Eventually, a link is created between the action and the emotion. They reinforce each other. Which implies that simple things like forcing yourself to smile when you feel bad may actually help you change the emotional state you are in.
I don’t know how much peer-reviewed literature is available to document this (hell, I’m not even sure how you would set up the experiment), but at least from a common-sense standpoint it seems reasonable enough.