This volume examines the role of League of Nations committees, particularly the Advisory Committee of Jurists (ACJ) in shaping the statute of the Permanent Court of International Justice (PCIJ). The authors explore the contributions of individual jurists and unofficial members in shaping the League’s international legal machinery. It is a companion book to The League of Nations and the Development of International Law: A New Intellectual History of the Advisory Committee of Jurists (Routledge, 2021). One of the guiding principles of the book is that the development of international law was a project of politics where the idea and notion of an international society must contend with the political visions of each state represented on the different legal committees in the League of Nations during the drafting of the Covenant. The book constitutes a major contribution to the literature in that it shows the inner workings of some of the legal committees of the League and how the political role of unofficial members was influential for the development of international law in the early twentieth century and how they influenced the political and legal process of the ACJ. The book will be an essential reference for those working in the areas of International Law, Legal History, International Relations, Political History, and European History.