This book is a response to Friedrich Nietzsche’s provocative question: How much and how does ressentiment condition our daily life? During the twentieth century we witnessed veritable eruptions of this insidious emotion, and we are still witnesses of its proliferation at various levels of society. This book aims to explore, according to René Girard’s mimetic theory, the anthropological and social assumptions that make up ressentiment and to investigate its genesis. The analysis of ressentiment shows that this emotion evolves from mimetic desire: it is an affective experience that people have when a rival denies them opportunities or valuable resources (including status) that they consider to be socially accessible. It is a specific figure of mimetic desire that is typical of contemporary society, where the equality that is proclaimed at the level of values contrasts with striking inequalities of power and access to material resources. This dichotomy generates increasing tension between highly competitive and egalitarian mimetic desires and growing social inequalities. The ressentiment is ambiguous, and its ambiguity is that of mimetic desire itself, which we cannot dismiss from our lives. In that it provides occasions of conflict and baseness, ressentiment can fuel violence, discord, and injustice, but it also can open opportunities for growth and justice, and for inventing institutions that are better adapted to the transformations of our contemporary society.