Surprised by Joy was published in 1955 as an autobiography of C.S. Lewis's spiritual journey.
The book recounts Lewis's intellectual and religious development from childhood through his eventual return to Christianity. Its central idea is “Joy,” a powerful longing or desire that Lewis describes as distinct from ordinary happiness and links to experiences of literature, imagination, and transcendence.
Lewis discusses his childhood in Belfast, his education, his service in the First World War, his friendships, and the changes in his beliefs. The narrative reaches his conversion to theism and later Christianity, although it is not a complete record of every event in his life.
A Grief Observed is sometimes confused with this book because it is also autobiographical. It is a later work about grief after the death of Lewis's wife, Joy Davidman, rather than an account of his earlier spiritual development.