“All illustrate the “theory of courage,” which Tolkien called “the great contribution of early Northern literature,” meaning both Icelandic and Old English literature. It is a “creed of unyielding will”: The heroes refuse to give up even when they know the monsters—evil—will win. For that is the big difference between Snorri’s Ragnarok and the Christian Doomsday. Odin and the human army of Valhalla do not win.”