How has one of the most extreme jihadist groups ever known gained a foothold across swaths of Iraq and Syria? How has ISIS exploited fault lines and built influence within key tribal areas? Syrian journalist Hassan Hassan delves deep into the tribal dynamics of the region, seeking to understand how ISIS has been operating, often with great success, alongside these groups for over a decade. Through first-hand experience, interviews with key tribal figures and ISIS members, Hassan demonstrates the central part tribes play within Iraq and Syria, and that the efforts to overcome ISIS must find a way to separate the jihadist movement from these groups on the ground.