There was a time when everyone pretty much knew what it meant to be a man, to the extent that anyone even asking the question would probably have earned a quizzical look. These days, manliness is as nebulous as concepts come, and Justin Davidson says that “masculinity is being constantly renegotiated, and men find themselves walking an invisible line, where self-assurance spills into arrogance, aggressiveness into bellicosity, stoic fortitude into cold indifference, sexual assertiveness into rapaciousness.”