What is the name of C.S. Lewis’s science-fiction trilogy featuring Elwin Ransom?

C.S. Lewis’s science-fiction trilogy featuring Elwin Ransom is The Space Trilogy.

The series consists of Out of the Silent Planet, Perelandra, and That Hideous Strength. The first novel appeared in 1938, followed by the second in 1943 and the third in 1945. Elwin Ransom, a philologist and university professor, is the central character in the first two books and an important figure across the series.

The trilogy combines planetary adventure with theology, philosophy, and criticism of modern technocratic power. In Out of the Silent Planet, Ransom travels to Mars, called Malacandra. Perelandra moves the action to Venus, while That Hideous Strength brings the conflict back to Earth.

The series is sometimes called the Ransom Trilogy because of its protagonist. The established title, however, is The Space Trilogy. It is separate from Lewis’s Chronicles of Narnia and from his apologetic works such as Mere Christianity.