The possibility of Britain withdrawing from the European Union - a "Brexit" - has been receiving growing attention. Reports have largely focused on what this withdrawal could mean for the United Kingdom; however, there has been little analysis of what it could mean for the rest of the Union, its individual members, wider Europe, and other states around the world such as the United States and Japan. This analysis gathers 26 views from think-tanks, research institutions, and universities from sixteen EU member states, nine non-EU countries, and a view from the EU’s institutions in Brussels. Five overall themes emerge from the contributions: 1. Developments in the UK have not passed unnoticed, but there are varying levels of understanding as to what is driving UK behavior as well as a great deal of uncertainty about the potential impact for the EU and the countries covered. While no country seems to be planning actively for a Brexit, many are aware that this step may become necessary because of developments in the UK’s domestic debate. 2. Awareness of the UK’s position is largely framed by wider concerns facing the EU, especially the euro zone. For many states, the UK is important, and the EU would be a lesser place without it. Yet while the UK’s reform agenda does appeal to some states, the real pressure for reform will remain within the euro zone. Reform agendas might happen to overlap with London’s, but with the euro zone continuing to move ahead, they might increasingly diverge. Countries within the euro zone, the pre-in countries, and even Denmark with its opt-out have focused on Germany and France for leadership and have tried to secure a place close to euro zone decision-making. London has become a bystander. 3. While there is some support for the UK’s positions on EU reform, conceptual clarity and language are crucial. States like the Netherlands and Germany seek better enforcement of the principle of subsidiarity, not repatriation. A multispeed EU is considered a possibility, but not - as the UK might hope ...