That Hideous Strength (subtitled "A Modern Fairy-Tale for Grown-Ups") is a 1945 novel by C. S. Lewis, the final book in Lewis's theological science fiction Space Trilogy. The events of this novel follow those of Out of the Silent Planet and Perelandra (a.k.a. Voyage to Venus) and once again feature the philologist Elwin Ransom. Yet, unlike the principal events of those two novels, the story takes place on Earth rather than in space or on other planets in the solar system.