From the very first day of the Nuremberg Trials, the author, who was brought in as a court psychologist, spoke privately with each of the defendants. He meticulously recorded his detailed conversations in a precisely kept diary. The book contains important factual as well as atmospheric background information about the main defendants' reactions to the proceedings. The experienced psychologist managed to gain the trust of the inmates. With all their subordinate justifications, political half-truths, and cynical explanations, they reveal their true characters to him. The diary presents the defendants not in the courtroom but during breaks and in their cells—in short, in a situation where they could largely set aside tactical considerations and express personal views.