As his parents finished packing the few personal belongings they were permitted to take out of Germany, the bespectacled 15-year-old stood in the corner of the apartment memorizing the details of the scene. He was a bookish and reflective child, with that odd mixture of ego and insecurity that can come from growing up smart yet persecuted. "I'll be back someday," he said to the customs inspector who was surveying the boxes. Years later, he would recall...