International security is a term which refers to the measures taken by states and international organizations, such as the United Nations, European Union, and others, to ensure mutual survival and safety. These measures include military action and diplomatic agreements such as treaties and conventions. International and national security are invariably linked. International security is national security or state security in the global arena.
By the end of World War II, a new subject of academic study, security studies, focusing on international security emerged. It began as an independent field of study, but was absorbed as a sub-field of international relations. Since it took hold in the 1950s, the study of international security has been at the heart of international relations. It covers areas such as security studies, strategic studies, peace studies, and other areas.