This book introduces the novel concept of fringe regionalism to the field of international studies. It examines how regions are practiced by peripheral borderlands rather than centrally planned, thus offering new avenues for researching regionalism beyond the conventional focus on formal intergovernmental organisations. Two in depth case studies, the Sahara and the Caucasus, provide the real-life application of the concept and the authors use the tensions between competing demarcations of the region, the regional nature of extra-legal economies and the narratives of cross-border identities to steer their empirical approach. Through thorough analysis, the volume applies the concept of fringe regionalism to regions previously neglected by conventional approaches. Frank Mattheis is Research Fellow at the Institut d'études européennes (IEE), Université libre de Bruxelles, Belgium, and Associate Researcher at the Centre for the Study of Governance Innovation (GovInn), University of Pretoria, South Africa. Luca Raineri is Research Fellow at the Sant'Anna School of Advanced Studies of Pisa, Italy. Alessandra Russo is Post-Doctoral Researcher at the Centre Emile Durkheim, Sciences Po Bordeaux, France.