Which 1933 book by C.S. Lewis is subtitled An Allegorical Apology for Christianity?

The Pilgrim’s Regress is C.S. Lewis’s 1933 book subtitled An Allegorical Apology for Christianity.

The full title is The Pilgrim’s Regress: An Allegorical Apology for Christianity, Reason and Romanticism. Lewis published it after his conversion to Christianity and used an allegorical journey to present intellectual and spiritual arguments. The structure deliberately recalls John Bunyan’s The Pilgrim’s Progress while pursuing Lewis’s own concerns.

The central figure, John, travels through a symbolic landscape and encounters characters and institutions representing ideas, temptations, and philosophical positions. Lewis later acknowledged that the book can be difficult because its private references and intellectual debates are not always obvious to modern readers.

The work is distinct from Mere Christianity, which developed from wartime radio talks and presents a more direct argument. It is also different from Surprised by Joy, Lewis’s autobiographical account of his intellectual and religious development. The 1933 date places The Pilgrim’s Regress near the beginning of his major Christian publishing career.