My dissertation takes as its starting point the recently opened records of the International Tracing Service (ITS) in Bad Arolsen, Germany. I investigate how Western governments - Washington, Bonn, and Paris - and the Red Cross used this humanitarian agency the Allies established in 1943 to locate and reunite civilians displaced by World War Two and Nazi policies, to promote and legitimize political and cultural agendas in the post-World War II era. I explore how epistemic anxieties born alongside the Cold War continually recoded the agency’s humanitarian and caritative mandate and sustained the desire to continue operations, even after tracing ceased in 1949. I analyze how those insecurities defined and were influenced by transatlantic involvement in the tracing service. Control over the ITS had immense practical and symbolic significance and I argue that the importance ascribed to the agency called the ‘archive of horror’ and ‘shop window of democracy’ by states and non-governmental organizations not only redefined humanitarianism, but also revealed deeper political tensions intimately connected to the legacy of World War II, Germany’s Nazi past, the struggle for postwar hegemony in Europe, and the Cold War.