IN 1932, IRENE SCHEFFLER, a vivacious, beautiful, young photographer, moved from the provincial town where she'd been raised to the city of Nuremberg. Her father wanted someone to keep an eye on her as she attempted to make her way in the world, and his old friend and business colleague, Leo Katzenberger, an urbane German Jew, agreed to help. He found her an apartment in a building he owned that adjoined the offices where he worked each day. A friendship...