In the current age of economic austerity, there is increasing pressure for the military in the United States and the United Kingdom (UK) to be streamlined, so as to be able to deliver more for less cost. This requires a whole new approach to warfare supported by additional skill sets, many of which are not currently readily or widely available within the military. These skills have become even more vital in the current security environment of networked global insecurities. As such, there is a need for the military not only to re-establish lost skills, but to develop new skills to enhance its ability to tackle the emerging security threats of the 21st century. One way in which such skills shortages can be addressed is by accessing existing skill sets within the civilian workforce, which can be achieved through the recruitment of reservists. Reservists have been utilized not only by the U.S. Army, but also by numerous armies around the world, including the UK, where the reliance on Reservists has increased significantly in recent years. However, recent reviews carried out by the UK Ministry of Defence (MoD) identified a range of deficiencies highlighting the need for UK Reserve Forces to be modernized so that they can be utilized in a manner that is efficient, cost effective, and sustainable. Consequently, this book explores the various types of reservist roles and deployment options, as well as factors that are both detrimental and beneficial to the recruitment, retention, and use of Reservists, highlighting areas where the UK experience is of potential relevance to the U.S. Army's future options.