Book excerpt: Unsettled Frontiers provides a fresh view of how resource frontiers evolve over time. Since the French colonial era, the Cambodia-Vietnam borderlands have witnessed successive waves of market integration, migration, and disruption. The region has been reinvented and depleted as new commodities are exploited and transplanted: from vast French rubber plantations to the enforced collectivization of the Khmer Rouge; from intensive timber extraction to contemporary crop booms. The volatility that follows these changes has often proved challenging to govern. Sango Mahanty explores the role of migration, land claiming, and expansive social and material networks in these transitions, which result in an unsettled frontier, always in flux, where communities continually strive for security within ruptured landscapes.