The Mysterious Affair at Styles is Agatha Christie’s first published novel, and the first mystery novel to feature the little Belgian detective Hercule Poirot. Summary of the Book Emily Cavendish, the wealthy owner of an estate in Essex, dies of strychnine poisoning. The only people who would have motive are her family, consisting of her husband Alfred Inglethorp, and her step children John and Lawrence. Emily’s money comes from her previous marriage, and she changes her will at least once a year. The day of her murder, she was heard arguing with someone, either her husband or John. Whoever the murderer was, it became obvious that this was a difficult case to solve. However, the murderer clearly had bad luck. Among the visitors in Styles Court was also a former British Army Officer in World War I named Arthur Hastings. Hastings realizes that this mysterious affair calls for an expert, and he knows just the right man for the job: his old friend, a little Belgian detective with an awe-inspiring moustache, Hercule Poirot.