Which C.S. Lewis book is a Christian allegory about a fictional pilgrimage?

The Pilgrim’s Regress is C.S. Lewis’s Christian allegory about a fictional pilgrimage. Published in 1933, it was his first published work of prose fiction.

The book follows a character named John as he travels through an allegorical landscape while seeking an island. Its structure and title deliberately echo John Bunyan’s The Pilgrim’s Progress, but Lewis’s work addresses modern intellectual movements and debates about Christianity.

Lewis wrote the book after his conversion to Christianity and used it to express ideas about belief, reason, desire, and spiritual awakening. Readers sometimes confuse it with The Pilgrim’s Progress, Bunyan’s earlier seventeenth-century classic. Lewis’s title signals the connection while presenting a different story and historical setting.