Which C.S. Lewis novel concludes his Space Trilogy?

That Hideous Strength concludes C.S. Lewis’s Space Trilogy.

Published in 1945, That Hideous Strength is the third and final novel in the sequence that began with Out of the Silent Planet in 1938 and continued with Perelandra in 1943. The story focuses less on travel between planets and more on a sinister attempt to reshape human society through technocratic power and manipulation.

The novel includes Mark and Jane Studdock, whose separate experiences place them near opposing forces. Elwin Ransom, the central figure of the earlier novels, also remains important to the larger conflict. The book blends science fiction, Arthurian imagery, social criticism, and Christian themes.

The title comes from a line associated with the English poet David Lyndsay, quoted in the novel’s epigraph. It is sometimes mistaken for the name of the trilogy itself, but the trilogy is commonly called the Space Trilogy or the Ransom Trilogy. That Hideous Strength is specifically its concluding volume.