The Murder of Roger Ackroyd is one Agatha Christie's most famous novels. Its fame rests on a narrative device, profoundly original in its day (1926): murderer and narrator are one and the same. The author was thoroughly pilloried by critics at the time for this. They considered her invention an unfair trick on readers, that broke the rules of detective fiction. Eighty years later, Pierre Bayard, a professor of literature and psychoanalyst, offers a fascinating deconstruction of the novel. Quite apart from the technical aspects of his analysis, Bayard reaches an absolutely convincing, yet astounding conclusion: Agatha Christie is guilty of a miscarriage of justice. The murderer cannot be Dr Sheppard, as Hercule Poirot so blithely asserts.