Hercule Poirot (pronounced Air-kyool Pwa-roe) is a fictional character, the primary detective of Agatha Christie's novels who appears in over 30 books. The character was born in Belgium, and has worked as a Belgian police officer, but moved to England after World War I and started a second career as a private detective. Poirot is remarkable for his small stature and egg-shaped head, his meticulous moustache, his dandified dressing habits, his absolute obsession with neatness, and his disdain for detective methods that include crawling on hands and knees and looking for clues. He prefers to examine the psychology of a crime, once even betting his best friend and sometime partner, Arthur Hastings, that he could solve a case simply by sitting in an easy chair and using his "little grey cells."

Like a large number of detectives of the early days of mystery fiction (including Miss Marple, Sherlock Holmes, and Father Brown), Poirot is an unmarried, presumably celibate individual.