Men have been the dominant sex since the dawn of mankind. Hanna Rosin notices that this truth is no longer true. At this moment women are no longer gaining on men: they have pulled decisively ahead. In this book Rosin reveals how this new state of affairs is radically shifting the power dynamics between men and women at every level of society, with profound implications for marriage, sex, children, work, and more. Rosin shows how the radically different ways men and women today earn, learn, spend, couple up-even kill-has turned the big picture upside down.