Agatha Christie is nearly synonymous with upper-class British mysteries, for good reason. She set the standard for the genre in over 60 novels and dozens of short stories, also creating two classic detectives: the fastidious Belgian, Hercule Poirot, and English spinster Jane Marple. No one could match Christie's knack for weaving clues into her stories, then turning the whole thing inside out -- shocking her readers every time.