Dame Agatha Mary Clarissa Christie, DBE (15 September 1890 – 12 January 1976), was an esteemed English writer known for her sixty-six detective novels and fourteen short story collections, particularly those revolving around her fictional detectives Hercule Poirot and Miss Marple. Christie's debut novel, 'The Mysterious Affair at Styles' (1920), introduced the iconic character of Hercule Poirot, a Belgian detective whose meticulous and cerebral approach to solving crime made him an instant classic. The novel exemplifies Christie's innovative use of the 'closed circle' of suspects, a literary device she adopted frequently, which added to the suspense and intricacy of her plots. Christie's works are characterized by their ingenious puzzles, red herrings, and an acute insight into the human psyche. Christie's wit and mastery of the genre have earned her the title 'the Queen of Mystery,' and her books have sold over a billion copies in English and another billion in foreign languages, making her the best-selling novelist of all time according to the Guinness World Records. Born in Torquay, Devon, England, Christie's writing career spanned over five decades, and she was made a Dame for her contributions to literature in 1971. Her legacy endures through the continued popularity of her characters, with 'The Mysterious Affair at Styles' remaining a touchstone within the genre.