From using internet, taking a plane or understanding the threat to peace and security, every aspect of human life is linked to the regulations governing relations between States and other international actors. This course seeks to provide students with a knowledge and understanding of the principles of public international law in order to enable them to extend their ability to evaluate and analyze legal issues in the international context, often dealing with topical concerns. Whether it is debates over the legality of the use of armed force, the protection of the environment or the extent of individual responsibility for war crimes, questions of public international law are essential to understand the world we live in.