Her books have sold more than a billion copies in English and another billion in a hundred foreign languages. She is the author of eighty crime novels and short-story collections, nineteen plays, two memoirs, and six novels written under the name Mary Westmacott. She first tried her hand at detective fiction while working in a hospital dispensary during World War I, creating the now legendary Hercule Poirot with her debut novel The Mysterious Affair at Styles. With The Murder in the Vicarage, published in 1930, she introduced another beloved sleuth, Miss Jane Marple. Additional series characters include the husband-and-wife crime-fighting team of Tommy and Tuppence Beresford, private investigator Parker Pyne, and Scotland Yard detectives Superintendent Battle and Inspector Japp. Many of Christie’s novels and short stories were adapted into plays, films, and television series. The Mousetrap, her most famous play of all, opened in 1952 and is the longest-running play in history. Among her best-known film adaptations are Murder on the Orient Express (1974) and Death on the Nile (1978), with Albert Finney and Peter Ustinov playing Hercule Poirot, respectively.