Which 1933 book is C.S. Lewis’s autobiographical account of his return to Christianity?

The Pilgrim’s Regress is C.S. Lewis’s 1933 autobiographical and allegorical account of his return to Christianity. Its subtitle identifies it as an allegorical apology for Christianity, reason, and romanticism.

The book follows a character named John as he travels through a symbolic landscape. The journey reflects Lewis’s intellectual and spiritual movement from childhood belief, through atheism and philosophical exploration, toward Christian faith.

Lewis wrote the book soon after his conversion and used the form of a modernized pilgrimage narrative. Readers sometimes identify Surprised by Joy as the answer because that later memoir discusses Lewis’s spiritual development in much greater autobiographical detail. However, Surprised by Joy was published in 1955, while The Pilgrim’s Regress appeared in 1933 and presents its account through allegory rather than straightforward memoir.