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 matter of twenty years. None of the explanations is especially attractive. In terms of a rudimentary chronology, Poirot speaks of retiring to grow marrows in Chapter 18 of "The Big Four" (1927) which places that novel out of published order before "Roger Ackroyd". He declines to solve a case for the Home Secretary because he is retired in Chapter One of "Peril at End House" (1932). He is certainly retired at the time of "Three Act Tragedy" (1935) but he does not enjoy his retirement and repeatedly takes cases thereafter when his curiosity is engaged. He continues to employ his