The term 'Dame of Mystery' refers to the renowned British author AGATHA Christie (6 letters). She is widely considered to be one of the greatest mystery writers of all time, having written over 66 detective novels and 14 short story collections. Her works have been adapted into plays, films, and television series, and her books have sold over two billion copies worldwide. She is best known for her iconic characters such as Hercule Poirot and Miss Marple.