The Mysterious Affair at Styles, written by Agatha Christie in 1920, is the first of her novels to feature Hercule Poirot. The small, fastidious Belgian is one of her most iconic characters and among the most famous fictional detectives in the world.
The story features many of the elements that have become icons of the Golden Age of Detective Fiction, largely due to Christie's influence. It is set in a large, isolated country manor. There are a half-dozen suspects, most of whom are hiding facts about themselves.