This document provides an overview of intergovernmental organizations (IGOs) and their history and functions. It discusses key IGOs including the United Nations, European Union, NATO, ASEAN, and others. The UN was founded after WWII to promote global peace, justice and cooperation. The EU expanded economic integration among European states. NATO was created as a military alliance against the USSR and to ensure European security with US support. Regional IGOs also formed to increase cooperation, as seen with ASEAN in Southeast Asia. IGOs allow countries to work together on issues that individual states cannot address alone.