"The Mystery of a Hansom Cab" is a mystery novel by Fergus Hume, first published in Melbourne in 1886. Set in late 19th-century Melbourne, the story begins with the discovery of a man's body in a hansom cab, prompting an investigation led by Detective Gorby. As the narrative unfolds, it delves into the city's social divisions, highlighting the stark contrasts between the affluent and the impoverished. The plot thickens with the involvement of the influential Frettlby family and their concealed secrets, including issues of illegitimacy and hidden relationships.