This book offers a topical inquiry into the legal and political limits of EU regulation in the field of risk and new technologies surrounded by techno-scientific complexity, uncertainty, and societal contestation. It uses agricultural biotechnology as a paradigmatic example to illustrate the complex intertwinement between environmental, public health, economic and social concerns in risk regulation. Weimer analyses the drawbacks of the EU approach to agricultural biotechnology showing that its reductionism, i.e. the narrow understanding of GMO risks as well as the exclusion of broader societal concerns related to environmental and social sustainability, has undermined both the legitimacy and effectiveness of EU regulation in this area. Resistance to this approach however has also triggered legal innovations prompting us to re-think EU internal market law, including the way in which it manages the tensions between unity and diversity, and between social and economic concerns. This text offers fresh and original insights into how far the EU can go in harmonizing regulatory approaches to risk. At the same time, it proposes new ways of re-thinking EU risk regulation to make it more responsive to different perspectives on risk and technology. A unique feature of this book is that it contributes to various strains of scholarship including risk regulation, internal market law, public administration, and studies of governance and regulation, as well as connecting these themes to broader debates about the legitimacy of European integration and new ways of differentiated integration. As a result it assists in re-imagining the EU internal market and its regulation as a site of diversity.