I read that when I was younger. Funny how whenever anyone questioned something in the book hubbard would just say 'read it again'. LaVey's satanic bible was more honest than that. I saw a doco on scientology recently after watching the first season of The Path. Very strange organisation.
If I remember it well, the book itself says to read it again. At the beginning, you are supposed to take a test on whether or not you are a good happy person (the test is framed to that you will fail - and feel bad for it), and then take it again after the first reading. And then read it again and do even better.
Most people perform better after each reading, and while the book does present some interesting nlp techniques, those results are also due to the words themselves beeing twisted out of their meaning. That's some creepy **** indeed, and I don't wish it to anyone.
If you're interested in the subject, Alex Gibney's Going Clear is a great docu!
I actually like the Satanic Bible, but it's the polar opposite of those creepy sects. When Hubbard said "Let everyone come to be, and be rewarded in Xenu's bossom", Lavey said "It's ok if you don't want to be one of us. You're not worthy anyway". I'm not a satanist by any means, but I find this arrogance refreshing.