The ABC Murders is a classic mystery novel from the Golden Age of Detective Fiction—the umbrella term for many British detective novels written from the 1920s to World War II. Christie achieved much of her fame in this period, and her novels reflect much of the key aspects of the genre: a central mystery that can be solved by the reader with careful attention to the text, containing a limited set of suspects. Pauline Dewan notes that Golden Age novels are often considered “clue puzzles” (Dewan, “Golden Age,” see “Further Reading and Resources” section for context). In the case of the ABC Murders, the introduction of Cust and the third person chapters that largely involve him provide more trails for the reader to follow. The detective is often not a member of law enforcement, though there are exceptions, as in Ngaio Marsh’s Inspector Alleyn series.

Golden Age novels depend far more on formula—the initial suspect who is ultimately exonerated, a series of crimes that offer increasing data for the sleuth—than depth of feeling or character development. Poirot and Hastings are not substantively altered by the work they do, nor is the focus on their inner lives or those around them.