In the academic world as well as in international development, after many years of being marginal, corruption has resurfaced as a major issue. This chapter outlines our understanding of corruption as a type of particularistic social allocation of public resources. It defines it in opposition to distribution based on ethical universalism and as the outcome of equilibrium between opportunities for corruption and constraints on elite behavior. We define what we understand as a virtuous circle—the passage from extractive to inclusive institutions—and why we decided to study them in this book. Throughout this chapter, we also explain step by step how we identified the criteria for contemporary achievers that managed to establish virtuous circles, and argue for the selection of the case studies presented in this volume. The chapter argues for a diagnostic tool nested in quantitative evidence and presents the different indicators that we can use in this context. Furthermore, the narrative presents two paths to better equilibria between opportunities and constraints. The paths look at the modernization of the state and the modernization of society. In this chapter we set the scene for the in-depth case studies offered in this volume. We trace evidence of why certain countries managed to establish virtuous circles and whether these changes are sustainable. In comparing results we hope to contribute to a better understanding of the paths to good governance.