In the years since the collapse of the Soviet Union, the Euro-Atlantic security setting has undergone fundamental changes. Institutions founded during the Cold War have been adapted, sometimes in anticipation of new challenges and in other cases in response to events. The report examines institutional development during the past decade. Case studies, representing "snapshots" of change, form an important part of the study. Included are NATO, the European Union, the Organization for Security and Cooperation in Europe, and the G-8. Addressed are numerous questions about whether these institutions have undertaken necessary and relevant changes. Are they now more capable of meeting regional and global security issues? What division of labor among them best manages or minimizes conflict and instabligity in the early twenty-first century? This report is the product of a two-year project on European security institutions undertaken by the Institute for Foreign Policy Analysis in association with the Fletcher School of Law and Diplomacy of Tufts University.