The Human Behaviour series seeks to explain some of the various quirks and eccentricities that people have. I haven't read any of these personally, but I have heard they were good, but they were published in 1974-1976 so some of the newer theories about behaviour won't be included.
Are you one of those people who sits in an abnormal psych class and thinks 'Hey! I do that'? If yes, then I wouldn't recommend reading these.