This chapter discusses the historical development and contemporary operation of international economic law, with a focus on trade, development, and monetary and investment relations. It pays particular attention to the emergence of the system with the 1944 Bretton Woods Conferences establishing the IMF and the World Bank, the adoption of the GATT in 1947, the revindications and influence of developing countries on the evolution of the system (with the declaration of a New International Economic Order), and the contemporary law of international trade (under the World Trade Organization) and foreign investment transactions (under investment agreements protected by investment arbitration organized under the ICSID).