Students of social movements have long struggled to explain why insurgencies occur where and when they do. In this excellent study, Heather Williams examines two contemporary Mexican movements—one rural, one urban—as a means to explain why unrest develops, when movements form, and what movement activists are likely to do once they manage to construct an organization and articulate a set of collective demands. Expanding on the work of Doug McAdam, Sidney Tarrow, Charles Tilly, and other scholars who have wrestled with these questions, Williams is concerned with the way in which Mexico's successive economic crises, and the implementation of neoliberal policies in response to these crises, influence the manner in which the dispossessed organize and press their demands on the state.