The Sign of the Four, first pub­lished by Arthur Conan Doyle in 1890 edi­tion of Lippincott’s Month­ly Mag­a­zine, is the sec­ond nov­el fea­tur­ing the icon­ic detec­tive Sher­lock Holmes and his loy­al friend Dr. John Wat­son, liv­ing togeth­er in their Lon­don 221B Bak­er Street apart­ment. Holmes con­tin­ues to show­case his excep­tion­al pow­ers of deduc­tion and inves­tiga­tive skills as he works to solve the mys­te­ri­ous case of Mary Morstan’s miss­ing father and the valu­able trea­sure that has been hid­den for years. The suc­cess of the nov­el fur­ther cement­ed Holmes’ sta­tus as one of the great­est lit­er­ary detec­tives of all time.