Highly Recommended 

These are the books that talk more in detail about the evolutionary perspective outlined in The Purpose of Life:

 The Moral Animal: Why We Are, the Way We Are: The New Science of Evolutionary Psychology by Robert Wright

The Red Queen: Sex and the Evolution of Human Nature by Matt Ridley

Why Beautiful People Have More Daughters: From Dating, Shopping, and Praying to Going to War and Becoming a Billionaire– Two Evolutionary Psychologists Explain Why We Do What WeDo by Alan Miller and Satoshi Kanazawa

The Elephant in the Brain: Hidden Motives in Everyday Life by Kevin Simler and Robin Hanson