“If I have taken a certain poetic license in describing the thoughts and feelings of various persons, it is because I believe I have set them down with a reasonable amount of accuracy. I may add that they have been “vetted” by my friend Hercule Poirot himself. In conclusion, I will say that if I have described at too great length some of the secondary personal relationships which arose as a consequence of this strange series of crimes, it is because the human and personal elements can never be ignored. Hercule Poirot once taught me in a very dramatic manner that romance can be a by-product of crime.”

Christie uses the Prologue to establish what makes this entry in the Poirot series unique. After Hastings explains that some of the chapters will be in the third person, to reflect that he was not present, he assures the reader that his narration remains reliable. He is, as ever, Poirot’s faithful chronicler, deferring to his friend’s judgement as to the accuracy of his reflections. Hastings further notes that the mystery involves more romance, indirectly acknowledging that this may be surprising or a departure from genre convention. It is Poirot himself who insists that romance and crime may occur together—an assertion which helps clue the reader in that motivation and emotion will be key aspects of the story to come.

“‘You’re looking in fine fettle, Poirot,’ I said. ‘You’ve hardly aged at all. In fact, if it were possible, I should say that you had fewer grey hairs than when I saw you last.’ Poirot beamed on me. ‘And why is that not possible? It is quite true.’ ‘Do you mean your hair is turning from grey to black instead of from black to grey?’ ‘Precisely.’ ‘But surely that’s a scientific impossibility!’ ‘Not at all.’ ‘But that’s very extraordinary. It seems against nature.’ ‘As usual, Hastings, you have the beautiful and unsuspicious mind. Years do not change that in you! You perceive a fact and mention the solution of it in the same breath without noticing that you are doing so!’”

This exchange gives the reader a sense of the passage of time since the first entry in the series, which took place in 1916: Hastings expects to find Poirot looking aged, but he does not. Poirot, for his part, is clearly a bit vain and proud of his appearance, and willing to make jokes at his friend’s expense. He, deadpan and serious, agrees with Hastings’s