Peter Singer has produced a highly commendable volume for the Cornell Studies in Security Affairs series on an area of study that has received relatively little attention within the academic world. Much of the existing literature focuses on the mercenary end of private military companies (PMCs) and ignores the breadth of the industry. Similarly, the debate on transformation has tended to focus on technology and changing approaches to the conduct of war; relatively little has concerned itself with the increasing role of the privatized military companies, yet, as Singer points out, 1 in 10 of those deployed by the United States in the most recent war in Iraq was a contractor. It is not just the scale of the industry at present (one estimate puts it at $100 billion per year) that makes it an important area for study. It is also that this industry covers the full spectrum of defense activities. It ranges from service provision at home to the provision of combat services and military units. This will become even more so as we move away from the linear battlefield and the idea of a front line melts away. Moreover, this is not just a Third World issue; virtually every state uses elements of the industry, with the United States being the largest user.

The volume is divided into three parts. The first examines the rise of what Singer refers to as “Corporate Warriors,” placing the industry within developments in military history. It rightly highlights that this is not a new phenomenon. We have seen private groups on the battlefield since biblical times, and Singer cites the example of the Swiss Guard that protects the pope as an example. He considers what distinguishes the industry and argues that what we are witnessing is the increasing privatization of security. He rightly highlights the role that this industry has had throughout the evolution of warfare and that the assumption that the state has a relative monopoly over war is incorrect both now and in the past. He also correctly focuses on more recent post–Cold War developments.

The second part then subdivides the industry along three lines: military provider firms using the case study of Executive Outcomes; military consultant firms using the example of MPRI: and military support firms using the case study of Brown and Root. While this gives the reader an appreciation of the breadth of the industry, it is inevitable that there have been developments since the volume was crafted as the process of transformation continues. For example, Executive Outcomes have left the industry while a number of new players have entered. The industry, like the rest of the defense sector, is undergoing significant change, and therefore any text written on it will suffer from the challenge of catch-up. Nevertheless, the taxonomy is a useful guide.

The third part then considers some of the implications of these trends and raises a series of questions. These include contractual dilemmas, the civil–military balance, and the moral dimension. It would be easy to argue that each of these questions needs more research, which they do, but this ignores the text's role in breaking into this new ground for others to develop in more detail. The text serves as an introduction, and its extensive bibliography and provision of a list of Internet addresses of PMCs are helpful means for further study.

Where Corporate Warriors is particularly good is in destroying the myth that the industry is for the Third World and not for the First World. It highlights how the world's leading militaries are using the privatized military industry to support the process of transformation and, more controversially, debating whether particular companies can take over particular roles and, indeed, operations. Here, the United Kingdom's Foreign Office Green Paper on the industry is particularly interesting because it suggests that governments, and indeed international organizations such as the United Nations, may at times be better advised to use such companies for some operations than to provide elements of their own armed forces. Such companies are accountable to those who pay them—an area that the United Nations has had problems with when it comes to members' contributions—and may provide a quality that is otherwise unachievable. While it is relatively straightforward to argue against such trends, particularly with regard to the whole issue of accountability, it is worth noting that when we look at the current contributions in Iraq, we often read that the United States is the largest contributor, followed by the United Kingdom. This is misleading. Private military companies collectively are the second-largest contributor to the coalition in Iraq. Moreover, the industry is seen by many policymakers as a means of allowing the transformation process to take place by freeing up capital. As we shift to what Mary Kaldor refers to as New Wars and Gwyn Prins the requirement for strategic raiding, we are witnessing First World powers looking to use their militaries to fulfill new tasks to achieve their political ends. PMCs have areas of expertise that militaries either never had or are reducing in order to focus resources elsewhere. For example, the United Kingdom has adopted a variety of financial models, such as Public Private Partnerships and leasing, in most areas of defense. These serve as a mechanism to raise capital for early modernization (e.g., the Joint Services Command and Staff College or the leasing of C-17s from Boeing) or to furnish capabilities that would otherwise be unaffordable by sharing them with the commercial sector (e.g., sealift and heavy vehicle transporters).