This book explores the connection between the grievances of ethnic groups and the onset of civil violence, distilling previous work by the authors and their co-authors using the Ethnic Power Relations (EPR) dataset on politically-relevant group dyads. The authors find that groups that are relatively poor, suffering from exclusion from political power, status reversal, or previous bouts of conflict are more likely to experience or engage in civil violence. The authors argue that grievances are often dismissed in the recent literature as central drivers of violence because much of the scholarship is based on data at the individual or state level, thus omitting important variables that are properly measured at the inter-group level. The volume is impressively coherent and extremely accessible, particularly given that it stitches together the findings of a disparate set of research projects with unique research designs and data analysis. Although the book mounts a powerful defense for grievances explanations, the authors admit that panel data analysis cannot properly test dynamic causal mechanisms. In the end, the answer as to why civil violence occurs is likely to involve aspects of both greed and grievances, suggesting that scholars may have mistakenly cast complementary explanations as competitive to one another. Since the authors present a well-specified mechanism for how collective grievances translate into violence, it would be welcome if in their future work they explore methods that more directly tests for the impact of collective grievances on conflict – methods that can capture these processes over time. Despite these reservations, this volume proved an excellent read and stands as a fine contribution to the contemporary study of the causes of civil violence.