+1 for The Selfish Gene, one of the best books I've read. If you have any interest in the process of evolution/natural selection, I highly recommend it. It's not as "political" or explicitly atheistic as some of Dawkins' more recent work either, so people who have a negative opinion of that sort of thing shouldn't be turned off by his name being on it.

It really is sad how many people would use a man's political leanings in the 2010s to dismiss the scientific book that made him famous in the 1970s.