The book includes “Diary of a Collaborator” by L.T. Osipova and memories of V.D. Samarin, ideological collaborators, for whom cooperation with the occupiers during the Great Patriotic War was a conscious choice. The published texts are a valuable source on the history and psychology of collaboration, the history of Nazi occupation policy and everyday life under occupation. This is also a source on the history of Soviet society: in the extreme conditions of war, the features of this society, value guidelines and behavioral stereotypes of people who were formed under Soviet rule or were forced to adapt to the Soviet way of life for almost a quarter of a century, manifested themselves especially clearly. The publication is preceded by an introductory article, which analyzes the phenomenon of ideological collaboration in the USSR during the Great Patriotic War.