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

The Pilgrim’s Regress was first published in 1933 as an allegorical fantasy about a spiritual journey. Its subtitle, An Allegorical Apology for Christianity, Reason and Romanticism, signals the book’s intellectual and religious aims.

The story follows John as he travels through a symbolic landscape while encountering figures and institutions representing different ideas. Lewis modeled the work partly on John Bunyan’s The Pilgrim’s Progress, but he also used it to explore his own movement toward Christianity and his responses to modern thought.

The book appeared before Lewis became widely known as a Christian broadcaster and apologist. Its unusual symbolism can make it harder to approach than Mere Christianity, which presents arguments more directly. The title’s apostrophe is also important: it refers to a pilgrim’s journey, echoing Bunyan’s famous earlier work.