The Sign of Four was the second novel featuring which famous fictional detective, following A Study In Scarlet?
Arthur Conan Doyle Sir Arthur Ignatius Conan Doyle KStJ, DL (22 May 1859 – 7 July 1930) was a British writer best known for his detective fiction featuring the character Sherlock Holmes. Originally a physician, in 1887 he published "A Study in Scarlet", the first of four novels about Holmes and Dr. Watson. In addition, Doyle wrote over fifty short stories featuring the famous detective.
Drury Lane (character) Drury Lane is a fictional detective created by Ellery Queen in the 1930s under the byline of Barnaby Ross. He is a retired Shakespearian actor who lives in a lavish castle on the Hudson River. His backstory involves leaving the theatre because he lost his sense of hearing, and the novels occasionally mention his lip-reading. He appeared in four mystery novels: "The Tragedy of X", "The Tragedy of Y", "The Tragedy of Z", and "Drury Lane's Last Case". These books were later reissued under the Ellery Queen byline.