The topic of the dissertation is the history of the resistance struggle of the KPD (Communist Party of Germany) against the National Socialist dictatorship and its secret police, the Gestapo (Secret State Police). The dissertation is divided into four parts. The first part of the work deals with the history of the Secret State Police. Initially, it focuses on the transformation of the Political Police of the Weimar Republic into a terror instrument of the National Socialist reign of terror. The work then continues with the establishment of the State Police station in Düsseldorf. The conclusion of the first part is dedicated to the methods of Hitler's secret police. In particular, it highlights the imprisonment of innocent individuals and torture, as well as the infiltration of informants, with special emphasis on the latter.