The Murder of Roger Ackroyd
Agatha Christie
 The book is set in the fictional village of King's Abbott in England. It is narrated by Dr. James Sheppard, who becomes Poirot's assistant (a role filled by Captain Hastings in several other Poirot novels). The story begins with the death of Mrs. Ferrars, a wealthy widow who is rumoured to have murdered her husband. Her death is initially believed to be an accident until Roger Ackroyd, a widower who had been expected to marry Mrs. Ferrars, reveals that she admitted to killing her husband and then committed suicide. Shortly after this he is found murdered. The suspects include Mrs. Cecil Ackroyd, Roger's neurotic hypochondriac sister-in-law who has accumulated personal debts through extravagant spending; her daughter Flora; Major Blunt, a big-game hunter; Geoffrey Raymond, Ackroyd's personal secretary; Ralph Paton, Ackroyd's stepson and another person with heavy debts; Parker, a snooping butler; and Ursula Bourne, a parlourmaid with an uncertain history who resigned her post the afternoon of the murder. Dr Sheppard's spinster sister Caroline is a favourite character among many and some say she could have been in another book. The initial suspect is Ralph, who is engaged to Flora and stands to inherit his stepfather's fortune. Several critical pieces of evidence seem to point to Ralph. Poirot, who has just moved to the town, begins to investigate at Flora's behest. The book ends with a then-unprecedented plot twist. Poirot exonerates all of the original suspects. He then lays out a completely reasoned case that the murderer is in fact Dr. Sheppard, who has not only been Poirot's assistant, but the story's narrator. Dr. Sheppard was Mrs. Ferrars' blackmailer, and he murdered Ackroyd to stop him learning the truth from Mrs. Ferrars. Poirot gives the doctor two choices: either he surrenders to the police or, for the sake of his clean reputation and his proud sister, he commits suicide. In the final chapter of Sheppard's narrative (a sort of epilogue), Sheppard admits his guilt, noting certain literary techniques he used to write the narrative truthfully without revealing his role in the crime or doing anything to suggest that he knew the truth, and reveals that he had hoped to be the one to write the account of Poirot's great failure: not solving the murder of Roger Ackroyd. Thus, the last chapter acts as both Sheppard's confession and suicide note. The final revelation uses meta-fictional tropes. The ending also opens up the question whether narrators can be trusted or not. Christie uses unreliable narrator again in 1967 novel Endless Night. Reader response to the ending varies from admiration of the unexpected end to a feeling of being cheated. In the novel, Christie has laid side by side two modes of gathering of information and building of hypothesis. One is Poirot's use of ratiocination, the other is the channel of gossiping, practised by almost all inhabitants of King's Abbott, in particular, Caroline. While even Caroline is able to interpret certain situations correctly, Christie privileges scientific mode of investigation by unveiling the murderer through Poirot.