Dreams

I've been having very vivid dreams and this has lead me to think more about dreams.
I'm also reading a book that deals heavily in dreams. So I was thinking what if there really were people who could go into other peoples dreams? What could you do to effect a person in the dream world other then wake them up. You could really control people if you could control their dreams. People frequently make a lot of decisions when asleep. Well they may not make the final decision but your subconscious works on it a lot. So if you could go in and influence what they were thinking on a subconscious level you could really effect what they did in the everyday world. I'll post more about dream stuff later I think. It seems like there is a lot of room to expand upon this.