Ever hear the one about the man who wakes up after a chance sexual encounter to discover he's been involuntarily relieved of one of his kidneys? Or the tiny gift-wrapped box from a recently departed lover that reveals a horrible secret? Everyone knows contemporary legends, those barely believable, often lurid, cautionary tales, always told as though they happened to the friend of a friend. Sometimes we pass them on to others unsure of their truthfulness, usually we dismiss them as mere myth. But these far-fetched legends tell us quite a bit about our deepest fears and fantasies.

In...