The history of the NKVD operation is the central element of the chain of events known as the Great Terror. The book reproduces and brings together all significant documentary evidence of all stages of mass repression, gives detailed author explanations about the direction of the main blow, the relationship between the center and the periphery, the role of punitive bodies, the participation of the party and the so-called. unorganized population in the operation, the controversial problem of the reliability of investigative cases is considered.