■ Abstract Sociologists have turned to collective identity to fill gaps in resource mobilization and political process accounts of the emergence, trajectories, and impacts of social movements. Collective identity has been treated as an alternative to structurally given interests in accounting for the claims on behalf of which people mobilize, an alternative to selective incentives in understand...

Organizations are very important in social movements, but they are not the whole story. Social movements are exceedingly complex phenomena encompassing the actions of organizations and their members, the actions of nonmembers in activities planned by organizations, and the actions of nonmembers in activities that organizations have nothing to do with, and may even oppose. Crowds and diffuse col...

Movements develop in coevolution with regimes and other actors in their environments. Movement trajectories evolve through stochastic processes and are constrained, but not determined, by structures. Coevolution provides a theoretical structure for organizing existing understandings of social movements and sharpening future research. Stochastic thinking is essential for recognizing the both the...