About the book: 2011 / Espionage and sabotage activities against Russia took on a wide scale during the First World War and continued in the 1920-1930s gg. Then foreign intelligence services tried to create a “fifth column” in the USSR in order to undermine the Soviet state with its help, and in the event of a new war, use the power of the “fifth column” for an internal attack on the Soviet Union. However, thanks to the skillful work of the NKVD, the “fifth column” in the USSR was completely eliminated. This largely predetermined the victory in the Great Patriotic War, since Germany did not have significant support in the Soviet rear and could not use the “fifth column” in the fight against its enemy. The book is a collection of unique (including analytical) materials about the methods of work of the espionage and sabotage underground in the USSR in the 1930s. and the response actions of the NKVD.