Agatha Christie 
The Mysterious Affair at Styles 

The Mysterious Affair at Styles is a detective novel that was written by Agatha Christie in 1916 and first published in 1920 to rave reviews. It introduces her famous detective Hercule Poirot, a Belgian refugee of the Great War, who settles in England near the home of his wealthy, recently widowed friend Emily Inglethorp. When the widow is found murdered via the administering of poison, Poirot uses his detective skills to solve the mystery. Featuring multiple red herrings and surprise twists, the book ushered in what is known as The Golden Age of Detective Fiction.