The study of inequality in its various manifestations is a well-established agenda in social sciences, but existing research has so far neglected its political causes and consequences. Our Cluster of Excellence will therefore focus on the politics of inequality. Its fundamental research objective is to understand the social, political, and institutional conditions under which a given distribution of resources becomes politicised or remains unaddressed. More specifically, we aim to explain when and why citizens consider particular distributions "unequal" and the extent to which these perceptions shape individual preferences about government policies ("perceptions"). We also analyze the conditions under which public grievances related to inequality either promote or impede political participation and mobilization at the individual and group level ("participation"), and we explore the potentially selective responses of political actors to public demands and mobilization efforts ("policies"). Taken together: Perceptions, participation, and policies are the three research areas of the cluster.