Rumors of horrors about concentration camps leaked out from Germany before the end of the war. Few people believed the stories at the time. But then came the ghastly facts of Nazi brutality, revealed by Allied liberating forces. Battle-hardened veterans, inured to the sight and smell of death, were sickened by what they saw. Staggering out to meet them were walking skeletons; their bodies stripped of flesh and their minds crippled by disease and starvation. General Dwight D. Eisenhower recorded that he had "never at any other time experienced an equal sense of shock." He urged Washington and London to send observers to see the indisputable evidence.
Adolf Hitler became chancellor in 1933, and began building a system of concentration camps soon after. Hitler regarded concentration camps as a primary necessity for the survival of Nazism. He told the German public that society needed to be purged of "...softness and sentimental philistinism...We have no time for fine sentiments. I don't want the concentration camps transferred into penitentiary institutions. Terror is the most effective instrument." The first inmates were communists and Jews, followed shortly by democrats, Catholic and Protestant clergy and nuns, criminals, trade union members, pacifists, gypsies, and Jehovah's Witnesses.
Documents include: correspondence; trial records and transcripts; investigatory material, such as interrogation reports and trial exhibits; clemency petitions and reviews; photographs of atrocities; newspaper clippings; and pamphlets.