Hercule Poirot met his lifelong friend, Captain Arthur Hastings, and solved the first of his cases to be published, "The Mysterious Affair at Styles". It is clear that Hastings and Poirot are already friends when they meet in Chapter 2 of the novel, as Hastings tells Cynthia that he has not seen him for "some years". Particulars such as the date of 1916 for the case and that Hastings had met Poirot in Belgium, are given in "Curtain: Poirot's Last Case", Chapter 1. After that case, Poirot apparently came to the attention of the British secret service and undertook cases for the
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