Yan Karlovich Berzin is a revolutionary and participant in the Civil War, who for many years headed the military intelligence of the USSR. O. Gorchakov’s book is an attempt to recreate a full-blooded image of this, without a doubt, unique person. Having touched upon the documents and memories characterizing the intelligence officer, the author resisted the temptation to construct his narrative as a complete sensation, but tried to be objective.

The author used not only available materials on Berzin, which can be found in open sources, but also secret documents and memories of Berzin's associates and friends.