This is book number 1920 in the Hercule Poirot Mysteries series.
There were not less than seven people at the fashionable estate in Essex, England, who might have abided Emily Inglethorp if she were more dead than alive. There were not less than seven motives and no fewer than seven apparently fool-proof alibis when the wealthy lady of Styles lay dead in her own bed. Had the perfect crime been committed?
Here is the famous first case that launched the legendary career of Hercule Poirot. Agatha Christie's brilliant and eccentric detective steps out of retirement and into the shadows of a classic mystery. The victim is a wealthy heiress. The suspects are her fortune-hunting husband, her jealous relatives, her hired companion, and others. The solution is a deadly scheme that can only be revealed by the master detective himself, Hercule Poirot.