The international system which was characterized by its bipolar structure until the end of the systemic conflict undergoes a process of change. New regional power centres seem to emerge in various parts of the world. Those centres have begun to position themselves in different roles in their regions. China seems to be on its way towards a position as hegemon in the Asia-Pacific region. India is trying to determine its foreign policy under new auspices after the end of the concept of non-aligned states. Brazil seems to be using its geostrategic position to dominate the South American continent. Those are some examples of the change in the international system from bipolarity to multipolarity. In order to restructure the international community, several approaches can be discussed. Will the United States of America be the world's only superpower? Or, will the United Nations be able to provide collective security? The lectures presented at the Summer Course on International Security 1997 attempt to at least partially answer these questions.