"Legitimacy in International Law" is a scholarly book that engages with the current debate surrounding the legitimacy of international law. In recent years, the question of whether international law generally lacks legitimacy or whether it has been subordinated to the realities of power has gained significance. The book also addresses the challenges arising from the adherence to international legal obligations, particularly concerning national interests. Furthermore, it critically examines the ability of certain international norms, such as the prohibition of the use of force, to motivate compliance. The perspectives gathered in this book come from an international and interdisciplinary conference forum organized by the Max Planck Institute for Foreign and International Law. The contributions provide new insights and analyses into the complex issues of legitimacy in international law.