BEING good-looking is useful in so many ways.

In addition to whatever personal pleasure it gives you, being attractive also helps you earn more money, find a higher-earning spouse (and one who looks better, too!) and get better deals on mortgages. Each of these facts has been demonstrated over the past 20 years by many economists and other researchers. The effects are not small: one study showed that an American worker who was among the bottom one-seventh in looks, as assessed by randomly chosen observers, earned 10 to 15 percent less per year than a similar worker whose looks were assessed in the top one-third — a lifetime difference, in a typical case, of about $230,000....