"The Mysterious Affair at Styles" is a detective novel by Agatha Christie, first published in 1920. It introduces the famous Belgian detective Hercule Poirot, who is called to investigate the murder of Emily Inglethorp, a wealthy woman found dead in her home. The story unfolds in a country estate, where various family members and staff become suspects. As Poirot delves into the case, he uncovers secrets and motives among the residents of Styles Court. The novel is notable for its intricate plot and clever resolution, establishing Christie's reputation as a master of the mystery genre.