Human Diversity by Charles Murray

Coverage of three main axes of diversity: Gender, Race, and Class.

The only one he goes into detail on is gender. I learned a lot about the current state of research into the physical and developmental origins of difference between people.

He seems very defensive and careful about the latter two, and doesn't have much to say at all - there were nearly no specific examples. The main issue he is trying to establish is what framework we should use to discuss such things.