Which C.S. Lewis work is the third book in his Space Trilogy?

That Hideous Strength is the third book in C.S. Lewis’s Space Trilogy.

Lewis published the novel in 1945, following Out of the Silent Planet in 1938 and Perelandra in 1943. Unlike the first two books, which focus heavily on journeys to other planets, That Hideous Strength is set mainly on Earth and presents a struggle involving science, power, bureaucracy, and the supernatural.

The story follows Mark and Jane Studdock as they become entangled with rival forces. The fictional National Institute of Co-ordinated Experiments, or N.I.C.E., represents a technocratic project seeking to reshape humanity through scientific and administrative control.

Some editions and reference works call the series the Space Trilogy, while others use Cosmic Trilogy. The individual titles remain the same. That Hideous Strength is therefore the final volume regardless of which name is used for the trilogy.