Born in 1890, Agatha Mary Clarissa Miller seemed destined for an ordinary middle-class British life. But after working at an apothecary during WWI — where she developed a keen interest in poison — and enduring an unhappy first marriage, she launched one of the most spectacular literary careers of the 20th century, selling more than 2 billion copies and reinventing the modern mystery with sharp, baleful, red-herring-strewn plots. She divorced her first husband — though not before what some say was staging her own disappearance in order to embarrass him — and found happiness with her second, an archaeologist. When Christie died in 1976 at age 85, she had finished 72 novels, 160 short stories, and 15 stage plays, including the world’s longest-running one, The Mousetrap.