The book by Yulia Zorakhovna Kantor is dedicated to one of the most “closed” topics in Russian history - secret contacts between the USSR and Germany between the First and Second World Wars. Why did Soviet Russia and Germany pursue military-political rapprochement and not break off contacts after 1933? How did this rapprochement affect the formation of two totalitarian regimes? How is the “military case” and repression in the Red Army connected with it? How did cooperation affect the militarization of the two states and what did they come up with in 1939? The book is based on unique, previously unknown documents from the Central Archive of the FSB of the Russian Federation, the Foreign Policy Archive of the Russian Federation, the Foreign Policy Archive of the Federal Republic of Germany, the Russian State Military Archive, the Bavarian Military Archive, the Russian State Archive of Socio-Political History, the Federal Archive of Koblenz and others.