Recent research demonstrates that the quality of public institutions is crucial for a number of important environmental, social, economic, and political outcomes, and thereby human well-being broadly conceived. The Quality of Government (QoG) approach directs attention to issues such as impartiality in the exercise of public power, professionalism in public service delivery, effective measures against corruption, and meritocracy instead of patronage and nepotism. The 38 chapters in this handbook offer a comprehensive, state of the art overview of this rapidly expanding research field and also identify viable avenues for future research. The initial chapters focus on theoretical approaches and debates, and the central question of how QoG can be measured. The remaining chapters examine the wealth of empirical research on how QoG relates to democratic accountability, ethnic diversity, human well-being, economic growth, political legitimacy, environmental sustainability, gender equality, social cohesion, and the outbreak of civil conflicts. A third set of chapters turns to the perennial issue of what contextual factors and policy approaches have proven successful (and not so successful) for increasing QoG. The QoG approach both challenges and complements important strands of inquiry in the social sciences. For research about democratization, QoG adds the importance of taking state capacity into account. For economics, the QoG approach shows that in order to produce economic prosperity, markets need to be embedded in institutions with a certain set of qualities. For development studies, QoG emphasizes that issues concerned with corruption are integral to understanding development writ large.