Clive Staples Lewis (29 November 1898 - 22 November 1963), commonly referred to as C. S. Lewis and known to his friends as Jack, was a Northern Irish academic, medievalist, literary critic, essayist, and Christian apologist. He is also known for his fiction, especially The Screwtape Letters, The Chronicles of Narnia and The Space Trilogy.Lewis was a close friend of J. R. R. Tolkien, the author of The Lord of the Rings. Both authors were leading figures in the English faculty at Oxford University and in the informal Oxford literary group known as the "Inklings". According to his memoir Surprised by Joy, Lewis had been baptised in the Church of Ireland at birth, but fell away from his faith during his adolescence. Owing to the influence of Tolkien and other friends, at about the age of 30, Lewis re-converted to Christianity, becoming "a very ordinary layman of the Church of England" (Lewis 1952, p. 6). His conversion had a profound effect on his work, and his wartime radio broadcasts on the subject of Christianity brought him wide acclaim. Later in his life he married the American writer Joy Gresham, who died of bone cancer four years later at the age of 45.Lewis's works have been translated into more than 30 languages and have sold millions of copies over the years. The books that comprise The Chronicles of Narnia have sold the most and have been popularized on stage, in TV, in radio, and in cinema.Lewis, C. S. is the author of 'Reflections on the Psalms', published 1964 under ISBN 9780156762489 and ISBN 015676248X.