Out of the Silent Planet is a science fiction novel by the British author C. S. Lewis, published in 1938 by John Lane, The Bodley Head. Five years later it was published in the U.S. (MacMillan, 1943). Two sequels were published in 1943 and 1945, completing the so-called Cosmic Trilogy or Space Trilogy. The fragment of another sequel, evidently set prior to Perelandra and That Hideous Strength, was published as "The Dark Tower" in a 1977 collection of short fiction by Lewis (deceased 1963) and essays by four others, The Dark Tower and Other Stories (Collins, ISBN 0-00-222155-1)