In 2010, Philippe Sands was invited to give a lecture on genocide and crimes against humanity at Lviv University in Ukraine, which he accepted with the intent of learning about the extraordinary city that was home to his maternal grandfather, a Galician Jew who had been born there a century before and who'd moved to Vienna at the outbreak of the First World War, married, had a child (the author's mother), and then moved to Paris after the German annexation of Austria in 1938. It was a life that had been shrouded in secrecy with many questions not to be asked and fewer answers offered if they were. As the author uncovered, clue by clue, the deliberately obscured story of his grandfather's mysterious life and of his mother's journey (alone?) as a child surviving Nazi occupation, Sands realized that his own field of humanitarian law had been forged by two men--Rafael Lemkin and Hersch Lauterpacht--each of whom had studied law with the same professors, in the city of his grandfather's birth, at Lviv University . . . Lemkin and Lauterpacht had not known one another at school and yet at parallel times had forged diametrically opposed revolutionary concepts of humanitarian law that had changed the world--and, Sands writes, that each had dedicated his life to having his legal concept incorporated as a centerpiece for the prosecution of Nazi war criminals . . . The author writes of a third man, Hans Frank, Hitler's personal lawyer, who, as governor-general of Nazi-occupied Poland, ordered the death of more than a million Jews and Poles, among them the familes of the author, and of Lemkin and Lauterpacht. Sands pieces together how all three lives converged in October 1946, in courtroom 600 of the Palace of Justice at the International Military Tribunals at Nuremberg.