When Roger Ackroyd is found murdered, the event rocks the little English village of King’s Abbot. Ackroyd was to marry the beautiful widow Ferrars, who’d died merely a few hours before of an accidental overdose of veronal. Who murdered Roger Ackroyd, and more importantly, why? Hercule Poirot comes to the little village to find the answers, and he soon discovers that this is going to be an unusual case.
are assumed to be the doctor’s private thoughts about Ackroyd’s murder. Poirot also confides in Sheppard and often asks his opinion of people within the town. Again, this action on the part of Christie serves to inspire confidence in the narrator; the reader does not suspect him because Poirot does not, and because Christie has, as in previous novels, established Poirot as a reliable source and a good judge of human nature.
Another aspect to the novel in regard to the narration is the comparatively small role that Poirot plays. The reader is accustomed to seeing him as the main character—almost as a master puppeteer who guides the movements of all around him. In fact, the readers expect Poirot to manipulate them, for this is the nature of crime fiction in general: The reader is manipulated by the detective to see things his or her way. Christie, however, chooses to radically depart from this formula. Instead of Poirot manipulating the reader, Sheppard manipulates both the reader and Poirot. The reader is unaware of this subterfuge, however, until the end of the novel, when all the other probable suspects have been eliminated and only Sheppard remains. The reader is then privy to Sheppard’s confession, and all the pieces to this very complex puzzle fall into place. (enotes.com)