What was the first book C.S. Lewis published after returning to Christianity?

The Pilgrim’s Regress was the first book C.S. Lewis published after returning to Christianity.

Published in 1933, The Pilgrim’s Regress: An Allegorical Apology for Christianity, Reason and Romanticism was Lewis’s first published work after his conversion. It presents a symbolic journey by a character named John, who seeks an answer to the dissatisfaction that has shaped his life.

The title deliberately recalls John Bunyan’s The Pilgrim’s Progress, but Lewis’s book also engages with modern intellectual movements and his own philosophical concerns. It combines autobiography, Christian argument, and allegorical fiction, making it different in form from the later BBC talks collected as Mere Christianity.

Lewis returned to the Christian faith during the late 1920s and early 1930s, influenced partly by conversations with writers including J.R.R. Tolkien and Hugo Dyson. His later books developed themes first explored here, including reason, desire, conversion, and the relationship between imagination and belief.