Noah Goldstein’s, Steve Martin’s (no, not that Steve Martin’s) and Robert Cialdini’s Yes! 50 Scientifically Proven Ways to Be Persuasive is a pop psych book, where a bunch of research in psychology is distilled into one readable volume.
by Jason - Color theory, "Four primary colors? Yes, why not? It’s the closest thing to the actual physiology without getting complex." (some pertinent info here http://news.ycombinator.com/item?id=2166494)