The stereotype of masculinity embraces many qualities. To be manly one must be brave, daring, and cool under fire. A man must be physically strong--tough, skillful, dexterous. And one must also be honorable, honest, and courteous. A man must not complain. A man must not lose control of his emotions. A man must not cry. Even today, many men would accept these qualities as defining masculinity. But how did our idea of manliness evolve? How long have...