Focusing on commonisation–decommonisation as an analytical framework useful to examine and respond to changes in the commons, the chapter contributions explore how natural resources are commonised and decommonised through the influence of multi-level internal and external drivers, and their implications for commons governance across disparate geographical and temporal contexts. It draws from a large number of geographically diverse empirical cases – 20 countries in North, South, and Central America and South- and South-East Asia. They involve a wide range of commons – related to fisheries, forests, grazing, wetlands, coastal-marine, rivers and dams, aquaculture, wildlife, tourism, groundwater, surface freshwater, mountains, small islands, social movements, and climate. The book is a transdisciplinary endeavour with contributions by scholars from geography, history, sociology, anthropology, political studies, planning, human ecology, cultural and applied ecology, environmental and development studies, environmental science and technology, public policy, Indigenous/tribal studies, Latin American and Asian studies, and environmental change and governance, and authors representing the commons community, NGOs, and policy. Contributors include academics, community members, NGOs, practitioners, and policymakers. Therefore, commonisation–decommonisation lessons drawn from these chapters are well suited for contributing to the practice, policy, and theory of the commons, both locally and globally.