Who wrote The Murder of Roger Ackroyd? Would Agatha Christie have made Marple and Poirot vouch for an unreliable narrator/murderer?

It is unlikely that the same personality who wrote most of Agatha Christie’s novels wrote this one, since both Caroline Sheppard (the prototype for Miss Marple) and Hercule Poirot are employed to establish the credibility of Dr. Sheppard, the narrator/murderer.

Caroline establishes his credibility by knowing him his whole life (they are siblings), and currently living with him, yet detecting nothing more about him than that he is “weak.” Poirot, through most of this novel, refers to him as a substitute Hastings, his former, trustworthy sidekick (like Sherlock Holmes’s Dr. Watson).

Whose idea was it to write a detective novel with an unreliable narrator? It was suggested to Agatha Christie by two people. James Watts said, “Why not have a Watson do the murder?” And Lord Louis Mountbattan “did not merely offer the device but explained exactly how it should be used. Agatha very rarely took advice on her plots…And only she could have pulled it off so completely. Only she had the requisite control, the willingness to absent herself from the authorial scene and let the plot shine clear” (1, p. 155).

My theory is that, when these suggestions were made, they were responded to by one of Agatha Christie’s personalities who, ordinarily, would have taken the role of a villain. In short, this novel was mostly written by the Dr. Sheppard personality, just as it appears to be.

This is not to say that regular Agatha Christie did not also participate. For example, on the first page of the novel, she may have made Dr. Sheppard begin two sentences with the phrase “To tell the truth” (2), which implies that he is a liar.

1. Laura Thompson. Agatha Christie: An English Mystery. Headline Review, 2007.

2. Agatha Christie. The Murder of Roger Ackroyd: A Hercule Poirot Mystery [1926]. New York, Black Dog & Leventhal, [?].