The Dynamics of Interstate Boundaries explains why some borders deter insurgents, smugglers, bandits, and militants while most suffer from infiltration and crisis. Grappling with an issue at the core of the modern state and international security, George Gavrilis explores border control from the nineteenth-century Ottoman Empire to twenty-first-century Central Asia, China, and Afghanistan. Border control strategies emanate from core policies of state formation and the local design of border guard institutions. Secure and open borders depend on institutional design, not on military power. Based on research in numerous border regions, this book advances the study of the state, local security institutions, and conflict and cooperation over border control. It holds critical lessons for policy makers and international organizations working to enhance border security in dangerous regions.