Which C.S. Lewis book begins with the character Ransom traveling to Mars?

Out of the Silent Planet begins with Ransom traveling to Mars.

Published in 1938, Out of the Silent Planet is the first novel in C.S. Lewis’s Space Trilogy. Its protagonist, Elwin Ransom, is kidnapped and taken aboard a spacecraft bound for Mars, which is known as Malacandra in the novel.

The book presents an imaginative encounter among different intelligent species and explores language, morality, religion, and humanity’s place in the universe. Lewis wrote it partly in response to what he viewed as spiritually impoverished or overly materialistic science fiction.

The two later novels are Perelandra and That Hideous Strength. Readers sometimes call the work the “Ransom Trilogy,” because Ransom is the continuing central character, but “Space Trilogy” is the standard name for the three-book sequence.