Small and insular economies are often treated as marginal to the global economic system. This book takes the opposite view: they are among the most revealing environments in which to understand how competition actually works.In these jurisdictions, market dynamics depart from standard assumptions. Scale is limited, entry is rare, and concentration is frequently structural rather than the outcome of strategic conduct. In such contexts, competition law cannot rely solely on the expectation of rivalry emerging over time; it must instead engage directly with enduring market power and constrained contestability.Bringing together contributions from competition authorities across diverse small and insular jurisdictions, this volume examines how legal frameworks are applied, adapted and, where necessary, reinterpreted. Through detailed country analyses and comparative insights, it highlights both the persistence of common principles and the diversity of institutional responses shaped by local conditions.The book advances a broader proposition: small economies are not edge cases, but critical test environments for competition policy. By examining how competition law operates where its assumptions are most exposed, it offers a deeper understanding of how those principles may need to evolve in an increasingly complex and uneven global economy.