How do men and women differ? Where do the differences come from? And how do they shape modern life?

Drawing on a century of research and a billion years of evolution, Steve Stewart-Williams explains why many sex differences appear despite socialization, not because of it; why in our mating and parenting patterns, humans are more like the average bird than the average mammal; and why sex differences are sometimes a sign of societal health rather than injustice.

Steve Stewart-Williams is a professor of psychology at the University of Nottingham Malaysia. His first book, Darwin, God, and the Meaning of Life, was published in 2010. His second, The Ape That Understood the Universe, was published in 2018. His new book is A Billion Years of Sex Differences.