The Defiant Border explores why the Afghan-Pakistan borderlands have remained largely independent of state controls from the colonial period into the twenty-first century. This book looks at local Pashtun tribes' modes for evading first British colonial, then Pakistani, governance; the ongoing border dispute between Pakistan and Afghanistan; and continuing interest in the region from Indian, US, British, and Soviet actors. It reveals active attempts by first British, then Pakistani, agents to integrate the tribal region, ranging from development initiatives to violent suppression. The Defiant Border also considers the area's influence on relations between Pakistan, Afghanistan, and India, as well as its role in the United States' increasingly global Cold War policies. Ultimately, the book considers how a region so peripheral to major centers of power has had such an impact on political choices throughout the eras of empire, decolonization, and superpower competition, up to the so-called 'war on terror'.