John Dickson Carr was an American author of detective fiction, who also wrote using the pseudonyms Carter Dickson, Carr Dickson and Roger Fairbairn. He is generally considered one of the greatest writers of so-called Golden Age of mystery fiction, and a master of the locked room mysteries, in which a detective solves crimes seemingly impossible to solve as they take place in a room with no apparent means of entrance or exit for the perpetrator. Often regarded as a British-style mystery writer, Carr resided in England for a number of years, and his novels have an English setting and English characters. His two best-known detectives, Dr. Gideon Fell and Sir Henry Merrivale, are both English. "The Judas Window," also published as "The Crossbow Murder," features Sir Henry Merrivale and is considered one of the best, if not the best, locked room mystery ever written.