▪ Abstract  From the complex literatures on “institutionalisms” in political science and sociology, various components of institutional change are identified: mutability, contradiction, multiplicity, containment and diffusion, learning and innovation, and mediation. This exercise results in a number of clear prescriptions for the analysis of politics and institutional change: disaggregate institutions into schemas and resources; decompose institutional durability into processes of reproduction, disruption, and response to disruption; and, above all, appreciate the multiplicity and heterogeneity of the institutions that make up the social world. Recent empirical work on identities, interests, alternatives, and political innovation illustrates how political scientists and sociologists have begun to document the consequences of institutional contradiction and multiplicity and to trace the workings of institutional containment, diffusion, and mediation.