The Sign of the Four and play adaptations insure this book: The Sign of the Four was also adapted for radio by Bert Coules in 1989 as part of BBC Radio 4's complete audio Sherlock Holmes, with Clive Merrison as Holmes, Michael Williams as Watson, and featuring Brian Blessed as Jonathan Small. The Sign of the Four The Sign of the Four (1890), also called The Sign of Four, is the second novel featuring Sherlock Holmes written by Sir Arthur Conan Doyle. Doyle wrote four novels and 56 short stories featuring the fictional detective. The story is set in 1888. "The Sign of the Four"
Adrian Conan Doyle mother died in 1940. He founded the Sir Arthur Conan Doyle Foundation in Switzerland in 1965. On his death, his sister Jean Conan Doyle took over as their father's literary executor. Adrian Doyle produced additional Sherlock Holmes stories, some with the assistance of John Dickson Carr. The basis of his production was to complete those tales referenced in his father's stories, which his father had never written. These additional Sherlock Holmes tales were written in 1952 and 1953, a hardcover collection of the stories was published as "The Exploits of Sherlock Holmes" in 1954. They have been reissued subsequently, while