The gods of Olympus are the most colorful characters of Greek civilization: even in antiquity, they were said to be cruel, oversexed, mad, or just plain silly. Yet for all their foibles and flaws, they proved to be tough survivors, far outlasting their original worshippers. In Egypt, the Olympian gods claimed to have given birth to pharaohs; in Rome, they led respectable citizens into orgiastic rituals of drink and sex. Under Christianity and Islam...