Which C.S. Lewis novel is the final book in the Ransom Trilogy?

That Hideous Strength is the final novel in C.S. Lewis’s Ransom Trilogy.

Published in 1945, it follows the earlier novels Out of the Silent Planet and Perelandra. The trilogy’s central figure is Elwin Ransom, a philologist whose encounters extend beyond Earth and involve spiritual and cosmic conflict. That Hideous Strength shifts much of its setting to Earth and combines speculative fiction with satire of bureaucratic power and distorted scientific ambition.

The novel takes place largely in England and focuses on the N.I.C.E., an organization whose technological and social plans threaten human freedom. Lewis drew on themes from medieval cosmology, modern science, and the dangers of treating people as material to be managed.

The title echoes a line from David Lindsay’s 1920 novel A Voyage to Arcturus. Readers sometimes call the sequence the Space Trilogy or Cosmic Trilogy; both labels are used, while “Ransom Trilogy” emphasizes the recurring protagonist. That Hideous Strength is the concluding volume regardless of the label.