This book places the insurgent group Boko Haram, which has terrorised northeastern Nigeria through the last six years, in an historical and cultural context. It examines cultural changes in the lands south of Lake Chad through deep time, showing how these ancient processes can help us think about Boko Haram's activities in the present. The archaeological and documentary record for this area is unusually rich for sub-Saharan Africa, and allows us to understand Boko Haram within an historical narrative that stretches back directly five centuries, with cultural origins that stretch even deeper into the past. One important way to understand Boko Haram is as a frontier phenomenon, the most recent manifestation of processes of horrific violence, identity production and wealth creation that have been part of political relationships in this area of Central Africa through the last millennium. In striking ways, Boko Haram resembles the slave-raiders and warlords who figure in precolonial and colonial writings about the southern Lake Chad Basin. In modern times, these accounts are paralleled by the activities of smugglers, bandits (coupeurs de route, 'road cutters') and tax evaders, illegal actors who stand in complex relationships to the governments of modern African nation-states. The borderlands of these states are often places where the state refuses to exercise its full authority, because of the profits and opportunities that illegal and semi-legal activities afford, among others to state officials and bureaucrats. For local people, Boko Haram's actions are thus to a great extent understood in terms of slave-raids and borderlands. Those actions are not some mysterious, unprecedented eruption of violence and savagery: they can be understood within local contexts of politics and history. This book is written to counter exoticised portrayals of Boko Haram's activities, and of the region as a whole.