The book introduces little-known pages of the history of military operations of German submarines on the communications of the Northern Sea Route deep in the rear of the Soviet Union during the Great Patriotic War. Particular attention is paid to the reconnaissance activities of the German military in the Arctic even before the start of World War II, the preparation and construction in the Soviet Arctic of secret bases for fascist submarines on deserted, remote islands and along the shores of the northern seas. These abandoned shelters have been virtually unexplored by anyone to date. “Polar wolves” of Admiral Dönitz keep many secrets and may pose a danger to the intensive development of the Arctic regions of Russia, which has emerged in recent years. In particular, this applies to the planned industrial development, together with foreign partners, of the rich Shtokman gas condensate field, discovered at the end of the 20th century, on the continental shelf of the central part of the Russian sector of the Barents Sea.