This symposium critically engages with the volume Experimentalist Governance in the European Union: Towards a New Architecture (2010), edited by Charles F. Sabel and Jonathan Zeitlin. “Experimentalist Governance” (EG) opens up an original theoretical perspective on the emergent governance architecture of the EU and sheds new light on developments in key policy sectors. This symposium brings together a transatlantic group of distinguished political scientists and legal scholars to discuss the added value of EG as a concept for analysis, its theoretical underpinnings, empirical relevance, and normative implications, in terms of legitimacy. Contributors discuss EG from different disciplinary and theoretical perspectives, referring to a variety of empirical examples in the EU context and beyond. The symposium closes with a response from the authors to their critics. This collection of essays sheds new light on debates around the nature of the EU and democratic governance beyond the nation state.