We humans are essentially primitive creatures, trying to fit into a modern world of our own making. Our bodies and emotions are controlled by instincts that formed in the Stone Ages. That genetic programming has not had time to change and is in constant conflict with the expectations of civilized society. What we are taught about sexuality does not feel right, and what we desire is often not allowed. If we are to live at peace with ourselves, we must understand what we are.

This book explains why sex is so pervasive and intrusive in our lives. The author offers a model of human reproductive strategies that is more realistic than the standard monogamous male-female dyad.

This subject matter naturally divides into three sections. The first explains how romantic love really works and why people fall into and out of love. The second explores the social structure of marriage and how it evolved from proto-human behaviors to modern cultures. The third reveals the biological and mathematical basis of sexual diversity and explains how homosexuality and bisexuality fit into the natural reproductive strategy of Homo sapiens.