Leading social scientists, empirical analysts, and policy practitioners demonstrate the various ways in which the insights of János Kornai, a renowned early analyst and critic of the command economies of Eastern European communist states, are stirring academic and policy discussions about current challenges. While dissecting the economic theories and practices in the Soviet Bloc, Kornai devised and applied concepts such as soft-budget constraints, rush versus harmonic growth, surplus versus shortage economy, non-Walrasian equilibrium, bureaucratic coordination, and the invisible power of the communist party. These concepts are commonly applied to a variety of issues in the contexts of fundamental transformation. The cases discussed in this volume include the transitional paths of post-communist economies, the pitfalls of East European market-building, economic repercussions of the dissolution of Yugoslavia, and the process of integration in the Eurozone. In conclusion János Kornai’s thoughts on a variety of research topics as well as the value of democracy are included as he delivered at the conference celebrating his 90th birthday in 2018.