Claim: Agatha Christie was a mystery writer.

The Mysterious Affair at Styles is a detective novel by Agatha Christie . It was written in the middle of the First World War , in 1916 , and first published by John Lane in the United States in October 1920 and in the United Kingdom by The Bodley Head -LRB- John Lane 's UK company -RRB- on 21 January 1921 . The US edition retailed at $ 2.00 and the UK edition at seven shillings and sixpence -LRB- 7/6 -RRB- .   Styles was Christie 's first published novel . It introduced Hercule Poirot , Inspector -LRB- later , Chief Inspector -RRB- Japp , and Arthur Hastings . Poirot , a Belgian refugee of the Great War , is settling in England near the home of Emily Inglethorp , who helped him to his new life . His friend Hastings arrives as a guest at her home . When the woman is killed , Poirot uses his detective skills to solve the mystery . This is also the setting of Curtain , Poirot 's last case .   The book includes maps of the house , the murder scene , and a drawing of a fragment of a will . The true first publication of the novel was as a weekly serial in the The Times , including the maps of the house and other illustrations included in the book . This novel was one of the first ten books published by Penguin Books when it began in 1935 .   This first mystery novel by Agatha Christie was well received by reviewers . An analysis in 1990 was positive about the plot , considered the novel one of the few by Christie that is well-anchored in time and place , a story that knows it describes the end of an era , and mentions that the plot is clever . Christie had not mastered cleverness in her first novel , as `` too many clues tend to cancel each other out '' ; this was judged a difficulty `` which Conan Doyle never satisfactorily overcame , but which Christie would . ''