The Sign of Four

The Sign of Four is a detective novel by Arthur Conan Doyle, first published in 1890. It is the second Sherlock Holmes novel, placing Holmes at the center of a longer-form case built around clues, observation, and deduction. Written in English, it belongs to the Sherlock Holmes canon and shows Doyle working in the crime and detective fiction mode that made the character so widely known.

This is a good fit for readers who like classic detective stories with a clear structure and a steady reveal of information. It also works well for anyone who wants an early Holmes novel and a direct look at the style that shaped later stories in the genre. The book connects naturally to other Holmes stories and to the broader tradition of crime fiction built around reasoning rather than action-heavy plot.