The historical study of borderlands has been unduly restricted by an emphasis on the legal, political, and geographical aspects of borders and by a state-centered approach. Too often, the question has been how states have dealt with their borderlands rather than how borderlands have dealt with their states – culturally, economically, and politically. This article outlines a comparative approach to the social dynamics (struggles, adaptations, and cross-border alliances) in regions bisected by borders, and it argues that borderland studies provide an indispensable corrective to historical narratives that accept the territoriality to which all modern states lay claim.