Which C.S. Lewis book was first published in 1933 as an allegorical fantasy about conversion?

The Pilgrim’s Regress was first published in 1933 as an allegorical fantasy about conversion.

The Pilgrim’s Regress: An Allegorical Apology for Christianity, Reason and Romanticism was Lewis’s first published work after his return to Christianity. Its protagonist, John, travels through a symbolic landscape while seeking an unnamed object of desire and encountering competing philosophies, ideologies, and religious positions.

The title deliberately recalls John Bunyan’s The Pilgrim’s Progress, but Lewis’s book is not a straightforward retelling. It reflects the author’s own intellectual path and his struggle to explain how reason, imagination, and Christian belief could fit together.

Some readers find the book’s references to contemporary debates difficult because many targets are less familiar today. That is why it is often read with an introduction or explanatory notes, unlike Lewis’s more immediately accessible apologetic works.