The Anglo-Scottish borderlands of the sixteenth and seventeenth centuries provide an excellent window into early modern state formation, diplomacy, and cross-border interactions during a key moment in history. In the early modern period, the Anglo-Scottish border was transformed from an established line of demarcation between two independent kingdoms into a political obstacle. The people and administrators of the borderlands faced intense pressure after the Union of the Crowns in 1603, as King James VI/I sought to eliminate the borderline and turn the region into the "Middle Shires" of a united Great Britain. This book shows that, though the official borderline disappeared after union, the unique administrative arrangements, social and economic bonds of kinship, and built landscape served to uphold the notion of continued separation between the kingdoms. It highlights the movement of peoples across the borderline, collaboration attempts between local officials, and the formation of temporary cross-border alliances but also the assertion of national differences through periodic lawlessness, conflict, and outright war. The book thus demonstrates the complexities of the common border zone and the significance of the border in shaping distinct national identities. JENNA M. SCHULTZ teaches in the Department of History at the University of St Thomas in St Paul, Minnesota.