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 guidance on how institutional allies can better align with these movements to drive change.