than the devil you don't," the old adage goes. But what can we truly know about the Devil?
Pelikan, a Yale professor of history, argues that "diabology," the study of the Devil, is a useful way to examine an age-old question: How can evil persist if men can freely choose God?
In the Old Testament, the Devil "functioned as one deity among many others." But the third century A.D., the Devil had become, to theolo- gians, the chief agent of evil in the world. Manichean heretics...