In this lecture, Philippe Sands discusses his most recent book East West Street: On the Origins of 'Genocide' and 'Crimes Against Humanity' — part historical detective story, part family history, part legal thriller — to connect his work on 'crimes against humanity' and 'genocide', the events that overwhelmed his family in Lviv during World War II, and the untold story at the heart of the Nuremberg trial that pits lawyers Rafael Lemkin and Hersch Lauterpacht against Hans Frank, defendant number 7, former Governor General of Nazi-occupied Poland and Adolf Hitler's lawyer.