In C. S. Lewis’s view, the world needs good science fiction. The powerful emotions often aroused by this genre—you either love it or hate it—should warn us, Lewis observes, from thinking of science fiction as something trivial. No, such stories do “something to us at a deep level.” Science fiction of the type Lewis liked best—stories where the “marvellous is in the grain of the whole work”—can enlarge our being and satisfy deep human longings. Science fiction can help us know reality more deeply and truly.