This book aims to explore the variety in organizational forms that exists in the European agri-food sector, and to identify an appropriate theoretical framework that includes a set of conceptual instruments to analyse this variety. Moreover, this framework should be helpful in the exploration of the relationship between organizations and the regulatory domain. The book focuses on organizational forms under two perspectives. First, it underlines the variety in organizational forms and their internal complexity. Second, it includes a series of case studies from different theoretical perspectives that highlight diversity within the agri-food sector, spanning from the adoption of standards to producer organizations. The book then proposes a conceptual foundation that can help in the design of applied theoretical frameworks to address the variety and the complexity of the organizational modes in agri-food supply systems.