Towards Zero.

Agatha Christie was an English writer and 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 six romances under the name Mary Westmacott. In 1971 she was appointed a Dame Commander of the Order of the British Empire (DBE) for her contribution to literature. She was initially an unsuccessful writer with six rejections, but this changed when The Mysterious Affair at Styles, featuring Hercule Poirot, was published in 1920. During the Second World War she worked as a pharmacy assistant at University College Hospital, London, during the Blitz and acquired a good knowledge of poisons which featured in many of her subsequent 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. According to Index Translationum, she remains the most-translated individual author – having been translated into at least 103 languages. And Then There Were None is Christie's best-selling novel, with 100 million sales to date, making it the world's best-selling mystery ever, and one of the best-selling books of all time.