Most people of faith are perfectly sane, of course, even those who commit atrocities on account of their beliefs. But what is the difference between a man who believes that God will reward him with seventy-two virgins if he kills a score of Jewish teenagers, and one who believes that creatures from Alpha Centauri are beaming him messages of world peace through his hair dryer? There is a difference, to be sure, but it is not one that places religious faith in a flattering light.