Co-management has been adopted internationally, across all types of natural resource settings, bringing resource users and others into governance with government. Multiple aspects of co-management have been studied, from power-sharing to social networks and accountability, identifying a wide range of concepts that form the foundations of co-management. By bringing together and interrogating a wide range of concepts, from all natural resource sectors, including forests, fisheries and grazing land, this book identifies how each concept contributes to the understanding and practice of co-management. Concepts such as collaboration, participation, institutions, power, community, cohesion, representation, accountability, trust, legitimacy, scale, rights, justice, values, identity and adaptation are reviewed. Each chapter reviews foundational literature and identifies key implications for co-management. These are brought together in a concluding chapter that identifies recurring themes from across the chapters and develops a social relational definition and conceptual framework for the understanding and practice of co-management.