Clive Staples Lewis (29 November 1898 – 22 November 1963) was a British novelist, poet, academic, medievalist, literary critic, essayist, lay theologian, broadcaster, lecturer, and Christian apologist. He held academic positions at both Oxford University (Magdalen College), 1925–54, and Cambridge University (Magdalene College), 1954–63. He is best known for his fictional work, especially The Screwtape Letters, The Chronicles of Narnia, and The Space Trilogy, and for his non-fiction Christian apologetics, such as Mere Christianity, Miracles, and The Problem of Pain.

Lewis and fellow novelist J. R. R. Tolkien were close friends. They both served on the English faculty at Oxford University, and were active in the informal Oxford literary group known as the Inklings. According to Lewis' memoir Surprised by Joy, he was baptised in the Church of Ireland, but fell away from his faith during adolescence. Lewis returned to the Anglican Communion at the age of 32, owing to the influence of Tolkien and other friends, and he became an "ordinary layman of the Church of England". His faith profoundly affected his work, and his wartime radio broadcasts on the subject of Christianity brought him wide acclaim.