This book shows why a fundamental right to an adequate environment ought to be provided in the constitution of any modern democratic state. The importance of securing provision for environmental protection at the constitutional level is now widely recognized. Globally, more than 100 states make some form of provision for environmental protection in their constitutions. A question more hotly debated, though, is whether the provision should take the stringent form of a fundamental right. This book is the first to examine the question from the perspective of political theory. It explains why the right to an environment adequate for one's health and well-being is a genuine human right, and why it ought to be constitutionalized. It carefully elaborates this case and defends it in closely argued responses to critical challenges. It thus shows why there is no insurmountable obstacle to the effective implementation of this constitutional right, and why constitutionalizing this right is not democratically illegitimate. With particular reference to European Union member states, it explains what this right adds to states' existing human rights and environmental commitments. It concludes by showing how constitutional environmental rights can serve to promote the cause of environmental justice in a global context. The book provides illustrations from around the world of how human rights and environmental concerns have been linked to date, and highlights precedents for the future development of a fundamental right to an adequate environment. It will be of value to policy-makers, lawyers, campaigners, and citizens concerned with environmental protection as a public interest and fundamental right. It will provide a valuable resource for students and teachers in politics, philosophy, law, environmental studies, and social sciences more generally. The book makes an original contribution to normative political theory by rethinking rights and justice in the light of contemporary issues and contexts.