magine a factory that pollutes the air. If the government closes it down, can the operator allege undue encroachment on his property? If the government remains inactive, can the neighboring farmer demand that his/her property must be protected? These two questions point to two dimensions of the interrelation between environmental concerns and property interests. Property is either used as a barrier to or as a quest for environmental protection. This book examines how the weighing up of property and environmental protection interests is determined by law. It discusses solutions found in the EU and in the Member States, looking both at regulatory and constitutional law. It is based on national reports, guided by a common list of questions. The book's crosscutting contributions highlight commonalities and differences, with a view to develop a European ius commune. This is framed by an analysis of the pertinent jurisdictions of the European Court of Human Rights, the Court of Justice of the EU, and Investor-State Arbitration.