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,
Poirot Investigates clue. According to Poirot, Miss Marsh proved her superior intelligence by employing Poirot to solve the case. The American edition of the book, published one year later, featured an additional three stories which did not appear in book form in the UK until 1974 with the publication of "Poirot's Early Cases". The review in "The Times Literary Supplement" of 3 April 1924 began with a note of caution but then became more positive: "When in the first of M. Poirot's adventures, we find a famous diamond that has been the eye of a god and a cryptic message that it