Human Sex Differences
How do nature and nurture conspire to produce average differences between men and women? How different are the sexes, anyway? Are we highly dimorphic like peacocks and deer? Or are we relatively monomorphic, like gibbons and sea dragons?

Kinship, Altruism, and Morality
If evolution is all about the survival of the fittest, why are people usually quite nice to each other? If natural selection favours organisms that aid their relatives, why are people often nicer to their friends and lovers? Is morality a part of human nature - or is it a social institution designed to control and constrain the destructive aspects of human nature?

The Philosophical Implications of Evolutionary Theory
Steve Stewart-Williams' first book came out in 2010. It's called Darwin, God, and the Meaning of Life, and it's about the implications of evolutionary theory for some of the central topics in philosophy: Is there a God? Does life have any ultimate meaning or purpose? Are human beings superior to other animals or is this just a human prejudice? Does evolutionary theory have implications for issues like euthanasia and animal rights? Does the theory imply that ultimately nothing is morally right or wrong?