The Space Trilogy, sometimes referred to as The Cosmic Trilogy or The Ransom Trilogy, is a trilogy of three science fiction novels by C. S. Lewis, famous for his later series The Chronicles of Narnia. A philologist named Elwin Ransom is the hero of the first two novels and an important character in the third.
The books in the trilogy are:
* Out of the Silent Planet (1938), set mostly on Mars
* Perelandra (1943), set mostly on Venus. Also known as Voyage to Venus
* That Hideous Strength (1945), set on Earth. In 1958, the publishing house Avon (now an imprint of HarperCollins) published a version called The Tortured Planet from which they had cut one-third of the book.