This is probably the definitive beginner text on evolutionary psychology and one of the easiest to get into. It’s a little depressing at first, realizing how ruthless many of our so called “good” feelings are. But then you realize that truth is better than ignorance, and you emerge seeing the world as it truly is for the first time. Also, a similar read is Why Beautiful People Have More Daughters, which is more of a Q&A approach to the subject and has contemporary edge.