What is the first published book in C.S. Lewis's Space Trilogy?

Out of the Silent Planet is the first published book in C.S. Lewis's Space Trilogy.

The science-fiction novel appeared in 1938 and introduces Elwin Ransom, a philologist who is abducted and taken to Malacandra, the name used for Mars in the story. The book combines planetary adventure with philosophical and theological questions about humanity, language, and moral corruption.

The trilogy continues with Perelandra, published in 1943, and concludes with That Hideous Strength, published in 1945. Although the books are connected, each has a distinct setting and narrative emphasis.

Readers sometimes mistake Perelandra for the opening volume because it is the most overtly Eden-like installment. The publication order, however, begins with Out of the Silent Planet, which established Ransom and the trilogy's imagined cosmic setting.