Dame Agatha Mary Clarissa Christie, (15 September 1890 - 12 January 1976) was an English writer. She is known for her 66 detective novels and 14 short story collections, particularly those revolving around her fictional detectives Hercule Poirot and Miss Marple. Christie also wrote the world's longest-running play, a murder mystery, The Mousetrap, and, under the pen name Mary Westmacott, six romances. In 1971 she was appointed a Dame Commander of the Order of the British Empire for her contribution to literature.

Christie was born into a wealthy upper-middle-class family in Torquay, Devon. Before marrying and starting a family in London, she had served in a Devon hospital during the First World War, tending to troops coming back from the trenches. During the Second World War, she worked as a pharmacy assistant at University College Hospital, London, acquiring a good knowledge of poisons which feature in many of her novels.

Guinness World Records lists Christie as the best-selling novelist of all time. Her novels have sold roughly 2 billion copies, and her estate claims that her works come third in the rankings of the world's most-widely published books, behind only Shakespeare's works and the Bible. She remains the most-translated individual author, having been translated into at least 103 languages. In 1955, Christie was the first recipient of the Mystery Writers of America's highest honour, the Grand Master Award. 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.