This book examines the dynamics of relations and substance of the nuclear negotiations between the Great Powers and Iran over the latter's nuclear program. It covers the developments that took place in the 12 years between 2003 and 2015, but also offers assessments of the period following the US withdrawal from the JCPOA, and of the current prospects and efforts to save the Iran Nuclear Agreement. This book will be of particular interest to students of nuclear proliferation, diplomacy, Middle Eastern politics, and international relations.