A Severe Mercy is an autobiographical book by Sheldon Vanauken, relating the author's relationship with his wife, their friendship with C. S. Lewis, conversion to Christianity, and subsequent tragedy. It was first published in 1977. The book is strongly influenced, at least stylistically, by the Evelyn Waugh novel Brideshead Revisited. It was followed by a sequel, "Under the Mercy", first published in 1985.