Hercule Poirot sort of obsessive-compulsive" in Poirot. As mentioned in "Curtain" and "The Clocks", he is fond of classical music, particularly Mozart and Bach. In "The Mysterious Affair at Styles", Poirot operates as a fairly conventional, clue-based and logical detective; reflected in his vocabulary by two common phrases: his use of "the little grey cells" and "order and method". Hastings is irritated by the fact that Poirot sometimes conceals important details of his plans, as in "The Big Four". In this novel, Hastings is kept in the dark throughout the climax. This aspect of Poirot is less evident in the later novels,
Hercule Poirot less in evidence, frequently passing the duties of main interviewing detective to a subsidiary character. In "Cat Among the Pigeons", Poirot's entrance is so late as to be almost an afterthought. Whether this was a reflection of his age or of Christie's distaste for him, is impossible to assess. "Crooked House" (1949) and "Ordeal by Innocence" (1957), which could easily have been Poirot novels, represent a logical endpoint of the general diminution of his presence in such works. Towards the end of his career, it becomes clear that Poirot's retirement is no longer a convenient fiction. He assumes a genuinely