This symposium summarizes the main conclusions of an interdisciplinary conference on Multilevel Governance of Interdependent Public Goods at the European University Institute, Florence, in Spring 2011 and reproduces 4 of the altogether 15 conference papers.1 This ‘Introduction’ identifies areas where global public goods theories need further research. The ‘keynote speech’ by WTO Director-General Pascal Lamy gives a unique policy perspective on ‘Global Governance: From Theory to Practice’. Inge Kaul’s paper on ‘Global Public Goods Theory: Explaining the Underprovision of International Public Goods and Corrective Strategies’ offers a summary—by one of the leading researchers on public goods theory—of the main ‘collective action problems’ impe...