Hikaru Yamashita's book is a sincere effort to study three fundamental aspects of peacekeeping: “i) why peacekeepers states and organisation engage in cooperative endeavour, ii) forms of cooperation and iii) implications of evolving peacekeeping cooperation” (p. 3). Chapter 1 provides a short deliberation on the primary working definition of peacekeepers. Further, the author argues that the term “peacekeeping” should reflect the diversity of actors without undermining the essence of evolving practice. Chapter 2 examines the contextual factors that have triggered co-operation, where Yamashita opines that “post-cold war peacekeeping has evolved into a multidimensional conflict management endeavour; this is because of the nature of the conflict which is more regional” (p. 13). Chapter 3 offers an analysis of co-operation theories, instrumentalism, constructivism, and institutionalism and merges these theories to analyze the potential effect on global security governance. In Chapter 4, he examines the two specific situations of Darfur and the Democratic Republic of Congo to consider how the joint peacekeeping collaborations produced effects conducive to global security governance on the operational level, and he discusses the positive and the negative implications of the joint partnership of the UN with the regional organization. Further, he acknowledges that he has not fully explored the utility of collective decision-making. Chapter 5, regarding joint decision-making in Macedonia, Afghanistan, and Congo, overlaps with Chapter 4 in the sense that it analyzes the several positive effects of collective decision-making in terms of legitimacy, credibility, and shared expectation. Another vital facet the author underscores in the chapter is about “contemporary peacekeeping increasingly nested in troika agreements—a peace agreement, Security Council resolutions and consent of the host government” (p. 142). Chapter 6 addresses the capacity-building assistance for African peacekeeping, due to the time spent on that continent in comparison to other regions. Chapter 7 is on global security governance and international co-operation, and chiefly deals with the emergence of global peacekeeping co-operation and its aftermath; the author succinctly identifies various positive signs and complications: “the evolving regime of peacekeeping cooperation brings reinforced capabilities, shared resources and better understanding to deal with complex regional issues” (p. 191).

In conclusion, the author reflects on the prospective possibilities for peacekeeping co-operation, and maintains that the future of peacekeeping co-operation will depend on three fundamental factors: “i) continued development of African Peacekeeping capacity, ii) leadership role of the UN, in further expanding peacekeeping cooperation and iii) the increasing role played by newer actors that adopt peacekeeping as their official role in mutual cooperation” (p. 195). Yamashita's book narrates the centrality of peacekeeping co-operation in the global security regime, drawing examples from the missions in Africa; moreover, the book dwells upon the critical feature that is the changing dimension of the peacekeeping operation in the global arena with the UN at the helm. The book is a precious addition to existing knowledge on peacekeeping co-operation and, despite the scant references to legal doctrines, the book eloquently focalizes on the pattern, models, and theorization of peacekeeping co-operation.