The Sign of the Four
- Series
- Sherlock Holmes
- Number
- 2
- Published
- 1 February 1890
- Formats
- Ebook, Paperback
The Sign of the Four, also called The Sign of Four, is an 1890 detective novel, 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.