The Mysterious Affair at Styles

A refugee of the Great War, Hercule Poirot settles in England near Styles Court, the country estate of his wealthy benefactress, the elderly Emily Inglethorp. When Emily is poisoned and the authorities are baffled, Poirot puts his prodigious sleuthing skills to work. 
 
Suspects are plentiful, including the victim’s much younger husband, her resentful stepsons, her longtime hired companion, a young family friend working as a nurse, and a London specialist on poisons who just happens to be visiting the nearby village. All of them have secrets they are desperate to keep, but none can outwit Poirot as he navigates the ingenious red herrings and plot twists that earned Agatha Christie her well-deserved reputation as the queen of mystery. 

Agatha Christie (1890-1976) wrote sixty-six crime novels and story collections, fourteen plays, and six novels under a pseudonym. Her books sold more than a billion copies in the English language and a billion in translation. According to Index Translationum, people translated her works into at least 103 languages, the most for an individual author. The most enduring figure in crime literature, she created Hercule Poirot and Miss Jane Marple. She also authored The Mousetrap, the longest-running play in the history of modern theater.