This volume addresses the puzzling resilience of communist regimes, which are the longest-lasting type of authoritarian polity to emerge since World War I. The individual chapters provide two types of explanations for this resilience. The first focuses on structural factors that increase longevity by limiting mass discontent and, correspondingly, by boosting legitimacy. At a general level, most chapters highlight how the careful management of economic performance and the strategic use of limited political reform facilitate resilience by limiting popular discontent. The chapters also examine how specific variables can promote resilience. Some focus on the use of ideology to create and maintain regime legitimacy. Others stress that longevity requires that regimes limit their susceptibility to revolutionary contagion. Still others argue that strategies of inclusion (admission to the communist party for private entrepreneurs and redistributive policies for the unenfranchised) limit the potential for the emergence of challengers to the regime. Finally, some chapters focus on the use of vertical and horizontal accountability to enhance the responsiveness of leaders to popular input and thus increase satisfaction with the regime. Although individually none of these arguments can explain resilience, taken collectively they identify some of the key domestic political variables that are conducive to the survival of communist regimes.