Historically, the U.S. military's Special Operations Forces (SOF) have had primary responsibility for training, advising and assisting foreign military forces. Today, although this mission has not been completely relegated to conventional forces, the National Security Strategies of the current and previous administrations direct the U.S. military services to organise, train and equip themselves to carry out these activities on a larger scale with conventional (non-SOF) forces. This responsibility in its broad sense of building the capacity of partner states has been termed "security force assistance" (SFA). This book presents the distillation of best practices and lessons learned from the contemporary operating environment in Iraq and Afghanistan with regard to security force assistance, and offers recommendations that build upon recent initiatives within the Department of Defense (DoD) to create a comprehensive approach to improve U.S. SFA.