Which 1955 book is C.S. Lewis’s spiritual autobiography?

Surprised by Joy is C.S. Lewis’s 1955 spiritual autobiography.

The book recounts Lewis’s intellectual and spiritual development from childhood through his return to Christianity. Its title refers to “joy,” Lewis’s term for a powerful longing or fleeting desire awakened by experiences of beauty, literature, myth, and imagination. He presents this longing as an important part of his movement toward belief.

Surprised by Joy is not a conventional day-by-day memoir and does not cover every period of Lewis’s life equally. It concentrates on formative experiences, education, reading, friendships, and changes in worldview. A Grief Observed is a different book, written after Joy Davidman’s death, while Mere Christianity presents arguments and broadcasts about Christian belief. Confusing those titles can obscure the autobiographical purpose of Surprised by Joy.