Annotation This systematic investigation of the interaction among international and European institutions provides both a theoretical framework for analysis and the first broad overview of this largely uncharted field of research. By offering detailed case studies and a systematic analysis of results, the book examines the effects of institutional interaction on environmental governance and explores the ways in which international and European Union policies can either reinforce or undercut one another. After a conceptual overview in which Oberthu r and Gehring identify three causal mechanisms by which institutional interaction can affect environmental governance, ten case studies apply this theoretical approach. Six cases use an international institution as their starting point and four begin with a European Union legal instrument. The international regimes examined include the widely known Convention on International Trade in Endangered Species of Wild Flora and Fauna (CITES), Convention on Biological Diversity (CBD), and World Trade Organization and United Nations Framework Convention on Climate Change (UNFCCC). The EU instruments analyzed include lesser-known directives on the protection of habitats, the deliberate release of genetically modified organisms into the environment, and air quality. The studies show that although conflict and interference among different regimes and institutions do take place, synergistic interactions are common. The findings on the importance of, and mechanisms behind, these outcomes offer valuable insights for both scholars and policymakers. Contributors:Beatrice Chaytor, Clare Coffey, Andrew Farmer, Thomas Gehring, John Lanchbery, Sebastian Oberthu r, Alice Palmer, G. Kristin Rosendal, Jon Birger Skj©Œrseth, Olav Schram Stokke, Ingmar von Homeyer, Jacob Werksman, J©?rgen Wettestad.