Recent years have seen renewed interest in the study of revolutions. Yet the burgeoning interest in revolutionary events has not been matched by a comparable interest in the development of revolutionary theory. For the most part, empirical studies of revolutions remain contained within the parameters established by the "fourth generation" of revolutionary theory. This body of work sees revolutions as conjunctural amalgams of systemic crisis, structural opening, and collective action, which arise from the intersection of international, economic, political, and symbolic factors. Despite the promise of this approach, this article argues that fourth-generation scholarship remains an unfulfilled agenda. My aim is to work within—and beyond—fourth-generation theory to establish theoretical foundations that can underpin contemporary work on revolutions. I do so in three ways: first, by promoting a shift from an attributional to a processual ontology; second, by advocating a relational rather than substantialist account of social action; and third, by fostering an approach that sees revolutions as intersocietal "all the way down."