Shady Networks offers unique insights into the criminal history of twentieth-century communist Poland. Built around case studies at the intersections of government institutions, business, foreign trade, and the criminal underworld, the book scrutinizes the organization of particular social settings, analyzing the circumstances, contexts, and mechanisms that enabled their growth. Shady networks existed in the Polish People’s Republic (PRL) irrespective of Marxist ideology and state institutions. They connected representatives of law enforcement, civil servants, party members, directors of state enterprises, and entrepreneurs with common criminals. They thrived because of widespread corruption, collusion, and superficial policing. At their base lay a stagnant state apparatus and the ineffectiveness of a centrally planned economy, which, when combined with the tight control of everyday activities and basic freedoms, paved the way for the emergence of black markets wherever there was scarcity, be it in money exchange or consumer goods manufacturing. The authors mostly focus on the two final decades of the PRL, from 1970 to 1990, when the security apparatus was already firmly in place, and when faced with the fall of communism, its representatives attempted to secure their future in the emerging capitalist order by all available means. This work is intended for historians, criminologists, and sociologists. It may also be of interest to other researchers of communist criminality, the underworld, and the black market, who wish to further their knowledge of the specific criminal ecosystem arising in totalitarian states.