Agatha Christie wrote professionally.
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 is best known for her 66 detective novels and 14 short story collections , particularly those revolving around her fictional detectives Hercule Poirot and Miss Marple . Guinness World Records lists Christie as the best-selling novelist of all time . Most of her books and short stories have been adapted for television , radio , video games and comics , and more than thirty feature films have been based on her work .