C.S. Lewis is a character that appears in every book of The Space Trilogy (and The Dark Tower) based on C.S. Lewis himself. Lewis is friends with Ransom, and they both are philologists. He is first introduced to the reader in the last chapter of Out of the Silent Planet, when Lewis accidentally stumbles across the word 'Oyarsa' and asks Ransom what the word means through a letter. Ransom then invites Lewis to come over his house and Ransom tells him the whole story of him travelling to Malacandra. In Perelandra, Lewis is the narrator rather then a side character, and Ransom tells Lewis of his adventure instead of Ransom being the narrator. In That Hideous Strength and The Dark Tower Lewis plays a very small role, usually only being in only a chapter or two.