When a dictatorial regime collapses the former power elite, the perpetrators, helpers and collaborators of the old regime do not vanish but, as history has repeatedly shown, manage to survive quite agreeably. This survival is made the more likely by the fact that many of them are, or make themselves, irreplaceable and indispensable as professionals. Such was the situation in Germany after the liberation from Nazism in 1945. In postwar Germany exposing the perpetrators was particularly difficult, because Germany was not liberated by a strong internal anti-Hitler opposition but by the Allied forces. So there was hardly a powerful group within Germany willing or capable of depriving the perpetrators of their continuing power. Denazification was not implemented by the Germans but by the Allies, and although the Nuremberg Trials were a great achievement, they hardly incited effective follow-up trials on the part of the German judiciary. Furthermore, the change of the international political scene with the rupture of the anti-Hitler coalition and the outbreak of the Cold War between the Soviet Union and the Western Allies, paralysed the denazification process in Germany. Former Gestapo and S S intelligence officers became most welcome experts for American and British intelligence operations in the East. Klaus Barbie is the best known example (1). The Soviet Union and communist regimes in Eastern Europe similarly recruited former Gestapo and S S officers for their own intelligence services (2). Doctor perpetrators in Germany enjoyed particular protection. Kurt Ploetner, SS doctor at Dachau concentration camp, in 1946 was requested by the French to be extradited to stand trial for having directed Mescalin experiments on French prisoners to 'eliminate their will'. US intelligence reported to the French authorities that they could not get hold of him because he was believed to be living in the Soviet zone (3). His experiments provided important material for the CIA's mind control experiments with cannabis, mescalin and LSD in the fifties and sixties (4). It is doubtful whether the American authorities ever made any effort to arrest Ploetner; he taught medicine at the University of Freiburg in the sixties and was interrogated by a Munich State attorney about his involvement in the fatal malaria experiments at Dachau. Yet the indictment was dropped in 1972. In fact he was never indicted for his mescalin experiments (5). In 1945, Karl Sperber, a Czechoslovakian doctor and survivor of Auschwitz, had the foresight to warn the world: 'There is a tradition that doctors do not