This cutting-edge volume brings together a diverse roster of scholars to shed light on the reconfiguration of twenty-first century Latin American regionalism. Reflecting on both the multiplicity of regional integration across Latin America (LA) and the theoretically pluralist turn in contemporary scholarship on LA politics and International Relations, this edited volume proposes an 'integrative pluralist' methodology to deciphering the complexity of regionalisation projects, from both above and below. The book charts the contemporary evolution of older regionalisation schemes, such as the Common Market of the South (MERCOSUR), as well as more recent twenty-first century regional innovations, including the Bolivarian Alliance for the Peoples of Our America-Peoples Trade Treaty (ALBA-TCP), Pacific Alliance (AP), and the Union of South American Nations (UNASUR). Complementing this more traditional institutional perspective, the book also charts the underexplored dynamics of regionalism from below, in the context of region-wide networks of political organisation among indigenous and peasant movements. Set against the backdrop of a more critical reading of the historical origins of regionalism, this volume aims to contribute to the ever-growing conversation among scholars within and beyond Latin America on the actors, processes, contradictions, and prospects for regional cooperation. In offering a more holistic perspective on Latin American regionalism from above and below, this volume will be of interest to both newcomers to the field and more seasoned scholars working within/across disciplinary boundaries, from International Relations and International Political Economy to Historical Sociology and Institutionalism. The chapters in this book were originally published as a special issue of Globalizations.