Hyper-Organization offers an institutional explanation for the expansion of formal organization in the contemporary era-in numbers, internal complexity, social domains, and national contexts. Much expansion is hard to justify in terms of technical production or political power, it lies in areas such as protecting the environment, promoting marginalized groups, or behaving with transparency. The authors argue that expansion is supported by widespread cultural rationalization characterized by scientism, rights and empowerment discourses, and an explosion of education. These cultural changes are transmitted through legal, accounting, and professionalization principles, driving the creation of new organizations and the elaboration of existing ones. The resulting organizations are constructed to be proper social actors, as much as functionally effective entities. They are painted as autonomous and integrated but depend heavily on external definitions to sustain this depiction. So expansion creates organizations that are, whatever their actual effectiveness, structurally arational. This book advances theories of social organization in three main ways. First, by giving an account of the expansive rise of ''organization'' rooted in rapid worldwide cultural rationalization. Second, explaining the construction of contemporary organizations as purposive actors, rather than passive bureaucracies or loose associations. Third, showing how the expanded actorhood of the contemporary organization, and the associated interpenetration with the environment, dialectically generate structures far removed from instrumental rationality.