Yah those books are quite interesting, I remember Free gave me a copy of Neil Strauss - The game, it was an interesting read, but I never read this NLP one yet, I hate reading books tbh, but I could spend all day reading stuff on a PC
He has other books like this as well, quite alot of people have studied these books they are quite popular, most guys wanna use them to try and pickup girls lol, I think that's pretty sad but hey it's their life