In a world facing convergent crises-where authoritarianism spreads, climate change accelerates, and violent conflict surges-an urgent call echoes through these pages. Drawing insights from research and practice, this volume reveals the indispensable role of popular nonviolent movements-using tactics such as strikes, boycotts, protest, and other acts of noncooperation-to counter these crises. It further offers insights into how institutional allies can better align with these movements to drive change.