This latest offering in the multivolume intellectual history of the United Nations focuses on "human security." Coined in the early 1990s, the term has been used by thinkers who have sought to shift the discourse on security away from its traditional state-centered orientation to the protection and advancement of individuals within societies. Although as much normative as it is analytic, the concept is now integral to the way large parts of the international community think about security. This impressive study explores the meaning and significance of the term and the ways in which the UN and associated agencies and experts brought it to life. MacFarlane and Khong provide a detailed account of the individuals, commissions, reports, and conferences that launched and disseminated the idea. But the authors are equally attentive to deeper transitions in globalization, state sovereignty, human rights, and collective violence. Accordingly, the book can be read as a serious effort to identify the ways that ideas spread and have consequences. (Indeed, the authors find that the idea of human security has traveled widely but that its actual impact on the policies of states is limited.) It can also be read as a critique of the concept: the authors worry that the term has been stretched to include so much of what afflicts the human condition that it has lost its analytic traction. What is even more troubling is that the new normative thinking about security has not been matched by even a glimmer of a global consensus on how to achieve it.