Obviously, spoilers ahead.
3. Murder in Mesopotamia
As a novel, Murder in Mesopotamia is interesting for a lot of reasons. For one thing, it’s one of the few Christie’s to use first-person narration: the Hasting novels have it, back when Christie was more consciously mimicking Conan Doyle. As does The Murder of Roger Ackroyd, in which the first-person narration is rather crucial to the plot.
Murder in Mesopotamia would be the same book if it were not narrated. Amy Leatheran, a gentle and practical middle-aged nurse, is no Hastings: we know that she is not staying around for more than one book, nor do we learn anything more about Poirot from her eyes. There really seems no reason for an observer to narrate, other than that it gives a slightly more personal feel to the book than the other, paint-by-numbers Poirots.
Amy Leatheran is asked to join a dig in Mesopotamia by archaeologist Dr Leidner, who is worried about his wife and wants her to be observed by a trained nurse. This is a cue for a lovely array of background details about life on a dig in Mesopotamia: something Christie was familiar with through her second marriage, to archaeologist Max Mallowan. It’s all very realistic and moderately interesting. In the background, we find out about Mrs Leidner’s first husband, a German spy. A week after Amy Leatheran arrives, Mrs Leidner is found dead. Whodunnit?
Her first husband, long thought dead. It then turns out that he was at the dig, in disguise, and Mrs Leidner didn’t recognise him. It stretches belief, but is just about plausible.
And then we find out that his alter-ego was….drumroll…Dr Leidner. Mrs Leidner’s first husband was in disguise as her second and she didn’t recognise him.