That Hideous Strength: A Modern Fairy-Tale for Grown-Ups (also released under the title The Tortured Planet in an abridged format) 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 (also titled 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 elsewhere in the Solar System. The story involves an ostensibly scientific institute, the National Institute for Co-ordinated Experiments, which is a front for sinister supernatural forces. (Wikipedia, CC BY-SA 4.0)