This chapter will explore the importance of history to socialist law. It will describe how the ultimately triumphant Leninist version of socialism valuing state centralisation drew heavily on a historically rooted imperial Russian practice of 'supervisory legality' that competed with and undermined binding judicial control of legality. This supervisory tradition—justified as a way of ensuring a centralised vertical of power for Party policy, as well as a method for efficiently entertaining and monitoring complaints from individual petitioners—enforced legality through a bureaucratic process of checking and rechecking administrative and judicial decision-making. This supervisory practice was transplanted to other socialist countries and remains influential to this day because of a continued value for centralised state power in the countries of the former socialist bloc. Current efforts at understanding legal systems and judicial reform in these countries requires understanding both the practices and institutions of this tradition of supervisory legality, as well as its internal justifications.