The book offers an in-depth analysis of the challenges of establishing authority within collaborative efforts. It introduces the concept of cumulative authority, arguing that communicating authority effectively is key to the creation and success of collaborations. Rice uses a communication-as-constitutive of organizations perspective to reconsider organizational authority, typically thought of in terms of leadership, as instead negotiated in communication among collaboration members as they attempt to influence the collaboration's direction. Drawing from an extensive two-year case study of emergency management collaborations, the book traces potential influences on collaborative authority, including members' knowledge and expertise, organizational structures and hierarchies, and the material world, including documents, technologies, and the natural environment. This book is a valuable empirical resource for organizational communication and management students and scholars. It will also appeal to community collaborators and organizers, and contains advice and reflection questions for practitioners.