Which 1955 book by C.S. Lewis presents his path from atheism to Christianity?

Surprised by Joy is C.S. Lewis’s 1955 book about his path from atheism to Christianity.

The work is an autobiography focused on Lewis’s intellectual and spiritual development. It traces childhood experiences, education, friendships, reading, and the gradual changes that led him away from atheism. Lewis uses “joy” for a particular kind of intense longing, not merely ordinary happiness or pleasure.

The book discusses major influences including George MacDonald, G.K. Chesterton, and J.R.R. Tolkien. Lewis’s conversion unfolded in stages: he first became a theist and later returned to Christianity. He described his conversion to theism as taking place in 1930 and his conversion to Christianity in 1931.

Surprised by Joy is not the same book as Mere Christianity, which grew from wartime radio broadcasts. It is also different from A Grief Observed, which addresses the death of Lewis’s wife.