1. International law governs relationships between sovereign states and helps address increasingly complex interactions and disagreements between nations in a globalized world. 2. There are three main types of international law: customary law based on consistent state practices, treaty law based on binding agreements between states, and resolutions which can help form the basis for later treaties. 3. Key international organizations that develop and apply international law include the United Nations and International Court of Justice, though states must still agree to be bound by international rules.