Agatha Christie was a legendary English writer who ranks as one of the best-selling authors in history. Christie wrote more than 65 crime novels, fourteen short story collections, and the classic play The Mousetrap in a career that spanned over fifty five years. The Mysterious Affair at Styles, published in 1920, is Christie's first novel. The book is set in England during World War I and centers around a murder mystery featuring many suspects with potential motives. The book is also notable for introducing readers to Hercule Poirot, a popular detective that appears in many of Christie's novels. The Secret Adversary, published in 1922, is Christie's second novel. The book centers around Tommy and Tuppence, who appear in three of Christie's other novels, as they form a business and are hired to do extremely dangerous work.