Since the emergence of the modern state system, governments have sought to regulate their affairs through international treaties and other types of intergovernmental agreement. For example, when it became known that emissions of certain chemicals destroyed the stratospheric ozone layer, governments agreed on a global treaty to ban such emissions. When Titanic sank in 1912, governments negotiated the International Convention for the Safety of Life at Sea. More than 1,300 international treaties have been concluded just to address environmental concerns, from the Agreement on the Conservation of Populations of European Bats to the United Nations Framework Convention on Climate Change. There is even an international Agreement Governing the Activities of States on the Moon and Other Celestial Bodies and an Agreement on the Rescue of Astronauts.In political science, the last 40 years have seen a tremendous number of studies on the emergence, maintenance and effectiveness of such international institutions, including fully fledged international organizations, specialized bodies and programmes, as well as intergovernmental treaty secretariats. And yet, it has become increasingly evident that such international institutions do not operate in a void. All institutions operate instead within complex webs of larger governance settings. Many regulations and policies under the United Nations Framework Convention on Climate Change, for instance, also affect the protection of biological diversity, along with policies on energy, trade, patent rights, civil aviation, shipping and migration. Climate change is addressed not only in meetings of the parties to the climate convention but also by the International Maritime Organization, the United Nations Security Council, the United Nations Development Programme, the International Bank for Reconstruction and Development and many other institutions. In short, international institutions in all their forms are important building blocks of global governance. And yet, they are only one part of the story. They are all part of a larger whole that shapes, enables and at times hinders the functioning of single institutions. We thus must look at this larger picture. Without a better understanding 1