This book addresses the role of tribal militias in the context of the fight against Al-Qaida. The intent is to enrich policy analysis and clarify options for future operations by focusing on past experience in order to identify the positive and negative aspects related to the use of such militias. The focus in this book is on Iraq and Yemen. However, many of the lessons learned may be applied more broadly. The thesis is that the capabilities which tribally-based militias provide may be one of the most efficient, cost-effective tools against Al-Qaida. In some cases, such militias can act as a force multiplier for U.S. Landpower forces, whether deployed on the ground in significant numbers, or, in other cases, if such militias can reduce the need for a U.S. commitment on the ground in environments that might present unfavorable conditions for a significant U.S. Landpower footprint. At the same time, given the complexity of the local political environment, tribal militias are no panacea, but can be a two-edged sword. Like any weapon, the use of tribal militias has to be understood and wielded with caution and skill in order to avoid unintended consequences.