By the spring of 1945, the Second World War was drawing to a close in Europe. Allied troops were sweeping through Nazi Germany and discovering the atrocities of SS concentration camps. The first to be reached intact was Buchenwald, in central Germany. American soldiers struggled to make sense of the shocking scenes they witnessed inside. They asked a small group of former inmates to draft a report on the camp. It was led by Eugen Kogon, a German...