Thoughts on Self-Help books?

Lately, I have been reading quite a few self-help books / psychology books revolving around the theme of bettering oneself. I read somewhere a while back that the self-help industry is worth over 10 billion US (not 100% sure) and so I was wondering what everyone thought about self-help books?

I personally am a fan of literature, especially Russian literature, however recently I have been reading a lot of the self-help genre.