Citizens' assemblies bring the shared wisdom of ordinary people into political decision making on the climate and ecological crisis. They are increasingly being used at local, national and even global levels. But with what impact? Can they take us beyond the shortcomings of electoral and partisan politics? Can they make a real difference? This book explains why climate assemblies have captured the imagination of governments and activists alike, exploring the ways they can have a meaningful impact on climate politics. This book charts the development of climate assemblies across Europe and beyond. It explores what ordinary people want, highlighting the ways in which assembly recommendations take us beyond current government policies and offer new visions and directions for change. It shows that not all assemblies are the same and that the context and design of climate assemblies have differed quite profoundly - as have their impacts on policy and public discourse. The book also lays out the key elements needed for climate assemblies to have sustained impact, providing essential insights for anyone wanting to run or advocate for them, and concludes with reflections on what we can expect from assemblies as they evolve. The transition to net zero and climate resilient societies requires deep social and economic transformations that will have significant impacts on citizens' choices and behaviours. Such a transition needs to engage the public directly and this book shows how climate assemblies can achieve this, allowing us to address the issues we all face together.