This book is based on the assumptions that the regional level of security has always been important, has grown in importance over the past seven or so decades, and has emerged as especially prominent with the end of the Cold War. Unfortunately, neorealists are unable to recognize the increasing importance of regional interactions because they focus exclusively on the global level. Equally regrettable is the fact that newer globalization perspectives are unable to capture regional security relations adequately because they, too, severely downgrade the importance of states and/or assume that reactions to forces like globalization do not meaningfully differ across regions. Consequently, these prominent theoretical schools are increasingly unsuccessful at making sense of reality.

To replace them, Barry Buzan and Ole Wæver offer “regional security complex theory” (RSCT), building on materialist concerns akin to those in neorealism as well as constructivist securitization theory (as advanced by Buzan, Wæver, and Jaap de Wilde, Security: A New Framework for Analysis, 1998). RSCT distinguishes between global powers able to exert influence across the entire world and regional powers able to exert influence only close to home. Since the projection of power for influence is costly (a materialist influence on their theory), most states' security relations are clustered within their region. RSCT thus focuses attention on security interdependencies within regionally based clusters: regional security complexes. Buzan and Wæver's RSCT offers a conceptual framework to describe each regional security complex according to its type, and thus facilitates regional comparisons while still allowing for global power influence.

Buzan and Wæver define regional security complexes on the basis of their judgment regarding the existence of durable patterns of amity and enmity among proximate states. To the extent that states securitize their relations with neighbors (due to traditional balance-of-power concerns about anarchy, or over differences of opinion about other issues), they comprise a regional security complex. The boundaries of regional security complexes are determined by geographical obstacles to interaction, or by “insulator” states that have little or no security interaction with others. Regional security complexes are classified according to their types. “Standard” RSCs have two or more local powers with a predominantly military-political security agenda. Standard RSCs can be further defined as conflict formations (rivalries and balance-of-power politics predominate), security regimes (alliances mitigate much of the conflict that otherwise would arise), or security communities (à la Karl Deutsch). “Centered” RSCs differ from standard ones in that anarchy no longer prevails. They can be centered by the presence of a superpower or great power that, by consent or coercion, dominates regional relations. They can also be centered by an agreement wherein regional institutions provide an organizing scheme for local relations. Yet more classifications are introduced in that RSCs can combine into larger “super complexes,” or can comprise “pre-complexes” and “proto-complexes” (RSCs in the making). Finally, historically there have also been “unstructured areas,” regions in which political actors are so primitive that there is insufficient interaction to speak meaningfully of security complexes at all. All states belong to no more than one regional security complex; there can be no overlap.

The bulk of the book is 10 chapters applying RSCT's classificatory scheme to all the different parts of the world. For each region, Buzan and Wæver describe why they believe a given set of states qualifies as a regional security complex, and then discuss that RSC in terms of its type and characteristics. They describe the patterns of hostility or friendship, the distribution of power, efforts by global powers to influence the region, and prospects for regional change. Not all of these applications are equally interesting or convincing, but this reviewer found their discussions of Africa, the Americas, and the post-Soviet space especially valuable. Perhaps this is because these regions are the most challenging for scholars who would analyze all the globe's regions within one theoretical scheme. An enormous amount of research, very well documented in the references, has gone into these 10 chapters, and they repay close reading even given their substantial length. The final two chapters of the book offer comparisons across regions and suggest avenues for further elaboration of RSCT.

As a quantitative researcher who has published a volume offering an alternative analysis of international security from a regional perspective (Douglas Lemke, Regions of War and Peace, 2002), I might be forgiven for complaining that Regions and Powers pays insufficient attention to establishing rigorous criteria by which the classification of states within specific regional security complexes could be replicated by others. In terms of an operational definition of RSCs, Buzan and Wæver claim: “In order to qualify as an RSC, a group of states or other entities must possess a degree of security interdependence sufficient both to establish them as a linked set and to differentiate them from surrounding security regions” (pp. 47–48). What might qualify as a sufficient degree of security interdependence or differentiation from other regions is never specified. Readers are forced to rely on their judgment. And yet, in spite of epistemological differences, the authors' regional security complexes are consistently similar to “regions” as defined using the (perhaps overly) precise coding rules that scholars of my ilk prefer. More significantly, their findings about the importance of regional rather than global matters in the security calculations of most states, and their claims that security dynamics vary profoundly across regions, are also very similar to those reached by more quantitatively oriented and mathematically inclined investigations. I was repeatedly struck by how complementary our analyses and conclusions are. If triangulation of research findings across different approaches is taken as especially strong evidence of the value of theoretical claims, then this convergence across studies suggests that efforts such as RSCT are very useful avenues for research on international security affairs. And so I strongly recommend Regions and Powers.