C. S. Lewis
After his conversion to theism in 1929, Lewis converted to Christianity in 1931, following a long discussion and late-night walk with his close friends Tolkien and Hugo Dyson. He records making a specific commitment to Christian belief while on his way to the zoo with his brother. He became a member of the Church of England – somewhat to the disappointment of Tolkien, who had hoped that he would join the Catholic Church.
The Screwtape Letters
The Screwtape Letters is a Christian apologetic novel by C. S. Lewis and dedicated to J. R. R. Tolkien. It is written in a satirical, epistolary style and while it is fictional in format, the plot and characters are used to address Christian theological issues, primarily those to do with temptation and resistance to it.