States of Transition takes a deep dive into the multiple roles states are playing in supporting transitions to a more sustainable world and where there is scope for their transformation. Going beyond unhelpful binaries - which cast the state as the central problem or the all-encompassing solution to ecological and social crises - it explores diverse current state practice across key domains: military, democracy, welfare, entrepreneurial, industrial, and foreign policy. It builds on theoretical resources from a range of disciplines, as befits the challenge of making sense of these diverse aspects of state power. It moves beyond existing analysis of the 'environmental state' to explore scope for a 'transition state' to emerge, capable of corralling and transforming all aspects of state power behind the goal of responding to the existential threat of planetary collapse. The book will be invaluable to students, academics, and practitioners concerned with environmental policy and sustainability.