Which C.S. Lewis autobiography describes his conversion to Christianity through the idea of joy?

Surprised by Joy is the C.S. Lewis autobiography describing his conversion through the idea of joy.

Lewis published Surprised by Joy: The Shape of My Early Life in 1955. The book traces his childhood, education, literary interests, service in the First World War, academic development, and movement from atheism toward Christianity. Its title refers to a distinctive experience Lewis called joy, an intense form of longing or desire connected with beauty, imagination, and transcendence.

The autobiography is not a complete account of every stage of Lewis’s life. It ends before many of his most famous publications and gives relatively limited attention to some personal relationships. Lewis’s conversion developed over several stages: he moved from atheism toward belief in God and later toward Christianity, influenced in part by conversations with J.R.R. Tolkien and Hugo Dyson.

Readers sometimes confuse Surprised by Joy with A Grief Observed, which is a meditation on bereavement after Joy Davidman’s death. They are different kinds of books: one is an account of intellectual and spiritual development, while the other records personal grief.