Why does having sons reduce the likelihood of divorce? Why are most neurosurgeons male and most kindergarten teachers female? Why is sexual harassment so persistent? Why do females in every culture tend to be more religious than their male counterparts? Why do so many politicians ruin their careers with sex scandals (but only if they are men)? These are some of the aspects of universal human behaviour into which evolutionary psychology has begun to give us insights. The past decade has witnessed an explosion in research on the biological and evolutionary foundations of our behaviour. And this new perspective is offering fresh insights into many questions that the social sciences have struggled to answer. Using a lively and engaging question-answer format, and with each chapter focusing on a particular theme of behaviour, the authors look the evolutionary reasons for the way we behave, the statistical trends and tendencies, and, of course, the many exceptions too.