House without a key. Azarov A.S., Kudryavtsev V.P.

In 1941, the Nazi counterintelligence managed to resolve several transmitters belonging to the Soviet center and who were in France, Belgium and Switzerland, after which an encoded designation of the operation - the Red Capella arose in the official documents of the Abwehr. However, a few groups of Soviet military intelligence officers continued to transmit information in great importance to the center. Many of the heroes of the book are not fictitious by authors and have real prototypes.