Why do girls do increasingly well in the classroom everywhere in the industrialized world, yet as adults demonstrate different career and life trajectories than men? By synthesizing recent evidence from the disciplines of developmental psychology, neuroscience, genomics, behavioral economics and education, Susan Pinker up-ends several common assumptions about the sexes: that male and female are developmentally and biologically equivalent, that ability is all it takes to succeed, and that women and men have identical life preferences and notions of success.