The women’s movement is one of the great success stories of the twentieth century, perhaps of any century. It is the story of a monumental, revolutionary transformation of the lives of more than half the population. But what about the other half? Today, this movement for women’s equality remains stymied, stalled. Women continue to experience discrimination in the public sphere. They bump their heads on glass ceilings in the workplace, experience harassment and less-than fully welcoming environments in every institution the public sphere, still must fight to control their own bodies, and to end their victimization through rape, domestic violence, and trafficking in women. I believe the reason the movement for women’s equality remains only a partial victory has to do with men. In every arena—in politics, the military, the workplace, professions and education—the single greatest obstacle to women’s equality is the behaviors and attitudes of men. I believe that changes among men represent the next phase of the movement for women’s equality—that changes among men are vital if women are to achieve full equality. Men must come to see that gender equality is in their interest—as men.