Melissa Hines is a professor of psychology and director of the Behavioural Neuroendocrinology Research Unit at the City University of London. She displays an impressive expertise in the biological and behavioral determinants of sex differences. This reflects her training both as a neuroscientist and as a clinical psychologist.

From the outset she reminds us that men are more likely than women to be incarcerated for violent crimes, to become university professors, to hold positions of political power, and to have above-average incomes. She also reviews a large body of scientific literature that indicates that the magnitude of sex differences is most marked for, in descending order, core gender identity, sexual orientation, height, mental rotation of three-dimensional objects (males are generally better