When is international patent law cooperation and harmonization welfare-enhancing? What is the role of international institutions - WIPO and the WTO - in furthering such harmonization? This book explores these questions from a global welfarist, rationalist perspective. It grounds its analysis in innovation theory and a examination of patent law and prosecution, incorporating the uncertainty of patent law's impact on welfare at a detailed level, dynamic changes, the skewed nature of patent value and the difficulty of textually capturing patent concepts. Using tools from new institutional economics, it explores future design implications for international institutions, analyzing grounds for international cooperation as collective action problems and applying historical, political and transaction cost analyses.