The result was The Mystery of a Hansom Cab, the first installment in a prolific career that saw the publication of some 130 books from 1886 until the author's death in 1932. He had to have Hansom Cab published privately because after spending a lot of time conducting research on Little Bourke Street in Chinatown in Melbourne, it was considered too scandalous of an exposé of contemporary Melbourne society. He also found publishers were prejudiced against an ex-pat Brit, as Hume noted, "Having completed the book, I tried to get it published, but everyone to whom I offered it refused even to look at the manuscript on the grounds that no Colonial could write anything worth reading."
Despite a disparaging comment from Arthur Conan Doyle that The Mystery of a Hansom Cab was "a slight tale, mostly sold by 'puffing'," Doyle was inspired by the work to write A Study in Scarlet, which introduced the character Sherlock Holmes. "Puffing" or no, Hume's debut novel went on to become the best selling mystery novel of the Victorian era, the Sunday Times called it "One of the hundred best crime novels of all time," and it spawned several film adaptations. In A Companion to Crime Fiction by Charles J. Rzepka and Lee Horsley, The Mystery of a Hansom Cab is called a "Most spectacular reimagining of the sensation novel, and a crucial point in the genre's transformation into detective fiction"
Although ground-breaking in detective fiction, it differed from more modern takes on the genre, such as having two detectives, with one (Detective Sam Gorby) starting off the first half of the story and then another (Kelsip) taking over in the second half. The story centers on the investigation into a homicide after a body, suffocated with a chloroform-soaked handkerchief sporting the initials OW, is discovered inside a hansom cab. Gorby discovers the deceased was Oliver Whyte, part of the social circle of wealthy Mark Frettlby, and romantically interested in Frettlby's daughter Madge.
The main suspect is an immigrant Irishman, Brian Fitzgerald, with whom Madge had fallen in love, causing rows between Fitzgerald and the dead man. Mark Frettlby, believing in Fitzgerald's innocence, hires lawyer Calton to defend him, aided by the second detective, Kilslip. Kilslip and Gorby have been rivals for years, which is why he also wrests the latter part of the investigation (and book) away from Gorby. The solution is tied to a Frettlby family secret and the class divide between Melbourne's wealthy and underclass societies.
Several reprints are available, and Project Gutenberg has an HTML E-text version online.