The darker side of Sherlock Holmes and the romantic side of Doctor Watson are both revealed in this enthralling second novel in Arthur Conan Doyle's detective series. Thick fog swirls through London, winding its way down Baker Street towards flat 221B where a cocaine-dazed Sherlock Holmes sits awaiting a new case. When a beautiful young woman, Mary Morstan, presents the sleuthing duo with two seemingly unrelated cases, all three work together to solve a decade-long mystery. A tangled web of missing fathers, curious deaths, and cursed treasure, The Sign of the Four was first published in 1890. This edition features a specially commissioned introduction alongside an article by Arthur Conan Doyle and an essay on the history of detective fiction by S.S. Van Dine.