A couple mentioned in that thread I enjoyed and recommend:
The Third Chimpanzee by Jared Diamond Really interesting read on human evolution, especially aspects dealing with sexuality. Some crossover with his other books, Why is Sex Fun (great book, also on topic!) and Guns Germs and Steel.
Clan of the Cave Bear by Jean M. Auel It's fiction, so perhaps not what you are looking for, but is a really great story! It's an immersive book and I feel having read it provides a great backdrop to fill in the details when playing Neanderthal. Helps me get into the theme so much more to have read this story. Note: I do not recommend any of the other books in this series, just the first.