Dan Stone tells the story of the last great unknown archive of Nazism, the International Tracing Service. Set up by the Allies at the end of World War II, the ITS has worked until today to find missing persons and to aid survivors with restitution claims or to reunite them with loved ones. From retracing the steps of the 'death marches' with the aim of discovering the burial sites of those murdered across the towns and villages of Central Europe, to knocking on doors of German foster homes to find the children of forced labourers, Fate Unknown uncovers the history of this remarkable archive and its more than 30 million documents.

Under the leadership of the International Committee of the Red Cross, the tracing service became one of the most secretive of postwar institutions, unknown even to historians of the period. Delving deeply into the archival material, Stone examines the little-known sub-camps and, after the war, survivors' experience of displaced persons' camps, bringing to life remarkable stories of tracing. Fate Unknown combs the archives to reveal the real horror of the Holocaust by following survivors' horrific journeys through the Nazi camp system and its aftermath.

The postwar period was an age of shortage of resources, bitterness, and revenge. Yet the ITS tells a different story: of international collaboration, of commitment to justice, and of helping survivors and their relatives in the context of Cold War suspicion. These stories speak to a remarkable attempt by the ITS, before the Holocaust was a matter of worldwide interest, to carry out a programme of ethical repair and to counteract some of the worst effects of the Nazis' crimes.