How often have I said to you that when you have eliminated the impossible, whatever remains, however improbable, must be the truth?
Sherlock Holmes, Chap. 6, p. 111
The Sign of the Four (1890), also called The Sign of Four, is the second novel featuring Sherlock Holmes by British writer Sir Arthur Conan Doyle. Doyle wrote four novels and 56 short stories featuring the fictional detective.