Not so long ago, unmarried men were called "bachelors," but the word now seems oddly out of date. Back in the day, bachelors were a minor, outsider group populated mostly by loners of ambiguous sexuality or Hefnerian swingers with a taste for cool jazz and dry martinis. Today, as men marry well into their 20s and 30s and enjoy both a boundless pool of sexually available women and a commercial culture awash with "stupid fun," the young, unmarried male has become a far more prominent -- and more vexing -- social type. He has devolved into the child man --...