This book provides an alternative approach to regionalism in neglected parts of the world. Taking stock of several decades of conceptualization, the author provides a political sociology approach of regionalisms fed by recent contributions from the sociology of international relations and public policy analysis. It uses a methodological rather than theoretical framework to bring a new perspective on an emerging field of comparative regionalism. The relational dimensions, the social contexts and characteristics of actors and their practices are key to shed a new light on what is considered in this book as a ‘social international phenomenon’.