This book analyses the establishment and operation of international agreements regulating trade in goods, focusing on the General Agreement on Tariffs and Trade (GATT). The book outlines the history of the international trading system from the creation of the first GATT agreement in 1947 to the establishment of the World Trade Organization in 1994. The major substantive provisions of the GATT are then analysed alongside the other foundational trade agreements of the WTO, clarifying the economic rationale for the current legal framework. Throughout the book it is maintained that the agreements themselves represent 'incomplete contracts', realized through interpretation by the WTO and other judicial bodies. A comprehensive analysis of the case-law is provided, where it is argued that a more rigorous theoretical approach is needed to ensure a greater coherence to the interpretation of the core provisions regulating trade in goods. The book presents an extension and elaboration of the author's views expressed in The General Agreement in Tariffs and Trade: A Commentary (OUP, 2005).