Drawing on the author’s personal experience, this book presents an insider’s chronology and policy analysis of the EU’s role in the nuclear negotiations with Iran. The European Union strives to be a global player, a “soft power” leader that can influence international politics and state behavior. Yet critics argue that the EU’s Common Foreign and Security Policy (CFSP) remains largely ineffective and incoherent. The EU’s early and continuous involvement in the effort to dissuade Iran from developing nuclear weapons can be viewed as a test case for the EU as a global actor. As Chair of the European Parliament’s delegation for relations with Iran, Tarja Cronberg had a ringside seat in the negotiations to prevent Iran from developing nuclear weapons. Drawing on her experiences leading a parliamentary delegation to Iran and interviews with officials, legislators and opposition leaders in nearly every country participating in the negotiations, as well as reports by the International Atomic Energy Agency, parliaments and independent experts, the author illustrates an insider’s strategic understanding of the negotiations. Intersecting history, politics, economics, culture and the broader security context, this book not only delivers a unique analysis of this historic deal and the twelve-year multilateral pursuit of it, but draws from it pertinent lessons for European policy makers for the future. This book will be of much interest to students of nuclear proliferation, EU policy, diplomacy and international relations in general.