This course aims to explore the roles International Organizations (IOs) play in international politics. In order to have a core set of analytical tools to apply to our study of specific IOs, we will begin the course with a both a historical and a theoretical perspective, considering various approaches, such as realist, liberal, constructivist, and institutionalist/bureaucratic arguments, as well as theories of marginalization. The course will then address the following questions, while analysing major IOs: why would states want to join an international organization? Why are IOs created? How can the IOs performance be evaluated, with what criterias? How do IOs evolve and change over time? What tools of influence or compliance IOs have at their disposal? The class’ main focus is on cooperation challenges in the international system and how international organizations are used, with different levels of success, to address them. Emphasis will be placed on students' ability to think critically, both about the nature of problems that face states as well as development of global governance mechanisms.