The grand dame of the cozy English murder mystery, Agatha Christie introduced Tommy and Tuppence, her duo of likeable upper-class detectives, in this 1922 novel, her second book. International intrigue, secret treaties, disguises, and blackmail follow this roguishly charming 1920s couple in their globetrotting quest to unravel the riddle of their disappearing client, disappearing diplomatic papers, and a devious plot that goes back to the sinking of the Lusitania. Beloved by Christie fans for their innocence and pluck, Tommy and Tuppence are a delight to spend quality crime-fighting time with. British novelist DAME AGATHA CHRISTIE (1890-1976) wrote more than 80 books, and is most famous for mystery series featuring detectives Hercule Poirot and Miss Marple. She is the best-selling fiction writer of all time, with more than one billion copies of her books sold in the English language, and another billion in 103 other languages.