Dame Agatha Mary Clarissa Christie, Lady Mallowan, (15 September 1890 – 12 January 1976) was an English writer known for her 66 detective novels and 14 short story collections, particularly those revolving around fictional detectives Hercule Poirot and Miss Marple. She also wrote the world's longest-running play The Mousetrap and six romances under the pen name Mary Westmacott.