Based on recent advances in economics, especially those in behavioral economics, this book elucidates theoretically and empirically the mechanism of time-inconsistent decision making that leads to various forms of self-destructive behavior. The topics include over-eating and obesity, over-spending, over-borrowing, under-saving, procrastination, smoking, gambling, over-drinking, and other intemperate behaviors, all of which relate to serious social problems in advanced countries. .