Agatha Christie was a writer.
Dame Agatha Mary Clarissa Christie , Lady Mallowan , DBE ( née Miller ; 15 September 1890 -- 12 January 1976 ) was an English crime novelist , short story writer and playwright . She was initially an unsuccessful writer , but this all changed for the better when The Mysterious Affair at Styles was published in 1920 featuring Hercule Poirot . The Mousetrap is a murder mystery play by Agatha Christie . The Murder of Roger Ackroyd is a work of detective fiction by Agatha Christie , first published in June 1926 in the United Kingdom by William Collins , Sons and in the United States by Dodd , Mead and Company on 19 June 1926 . Witness for the Prosecution is a play adapted by Agatha Christie from her short story .