Which 1955 book contains C.S. Lewis's account of his conversion and early intellectual life?

Surprised by Joy contains C.S. Lewis's account of his conversion and early intellectual life.

Lewis published Surprised by Joy: The Shape of My Early Life in 1955. The book is an autobiography focused mainly on his childhood, education, reading, imaginative development, and movement from atheism toward Christianity. It does not cover his entire life; the narrative ends before the later stages of his public career.

The title refers to Lewis's use of the word joy for an intense, elusive longing that he associated with certain experiences of beauty, literature, and imagination. He distinguishes this longing from ordinary happiness and presents it as an important thread in his intellectual and spiritual development.

Readers sometimes confuse this book with A Grief Observed, Lewis's later reflections after the death of his wife, Joy Davidman. They have different subjects and were published under different circumstances. Surprised by Joy is primarily an account of Lewis's early formation and conversion, not a conventional day-by-day autobiography.