No one knows if there was a man named Homer, but there is little doubt that the epic poems assembled under his name form the cornerstone of Western literature. The Iliad and the Odyssey-with their incomparable tales of the Trojan War, Achilles, Ulysses and Penelope, the Cyclops, the beautiful Helen of Troy, and the petulant gods-are familiar to most people because they are so pervasive. They have fed our imaginations for over two and a half millennia,...