The Mystery of a Hansom Cab is a mystery fiction novel by English writer Fergus Hume. The book was first published in Australia in 1886. Set in Melbourne, the story focuses on the investigation of a homicide involving a body discovered in a hansom cab, as well as an exploration into the social class divide in the city. The book was successful in Australia selling 100,000 copies in the first two print runs. It was then published in Britain and the United States and went on to sell over 500,000 copies worldwide, outselling the first of Arthur Conan Doyle's Sherlock Holmes novels, A Study in Scarlet (1887).