This is the first volume to comprehensively and systematically study, describe, and theorize the financial obligation created and governed by public international law. Legal globalization has given rise to a number of financial issues in international law in areas as diverse as development financing, investment protection, compensation of human rights victims, and sovereign debt crises. The claims resulting from the proliferation of financial activity are not limited to those primarily involving financial obligation (e.g. loans and grants) but include secondary obligation resulting from the law on international responsibility. Among the many instances of financial obligation covered in this study, the reader will find inter-State financial transactions, inter-State sale of goods, transnational services such as telecommunications and post, the financial operations of multilateral institutions, loans, grants and guarantees provided by the various international financial institutions, certain financial relations between non-State actors (including natural persons) and States, intergovernmental organizations or other international legal actors, and government loans to international organizations. Rich in historical detail and systematic in its coverage of contemporary law, this book will be valued by all practitioners and scholars with an interest in the nature of international financial obligation.