"The Queen of Mystery has come to Harper Collins! Agatha Christie, the acknowledged mistress of suspense-creator of indomitable sleuth Miss Marple, meticulous Belgian detective Hercule Poirot, and so many other unforgettable characters-brings her entire oeuvre of ingenious whodunits, locked room mysteries, and perplexing puzzles to Harper Paperbacks. In her classic The Big Four, the great Poirot is caught up in a deadly game of international intrigue as he races to uncover the strange mystery of "Number Four.""