Since the end of the Cold War peacebuilding in war-torn societies has become the most important task on the agenda of the United Nations. Between 1990 and 2005 the organization engaged in dozens of operations to help secure the peace. Many of these were Bmultidimensional^ operations, which seek to build, re-build, or reform the basic institutions of a post-civil war state. It is these most complex, difficult, and often successful operations that are the focus of Michael Doyle and Nicholas Sambanis_ timely and first-rate book, Making War and Building Peace. The purpose of the book is to Bdiscuss theories of the origins of and solutions to civil wars, the principles behind and the practices of the United Nations as an institution, and the debate over doctrines and strategies of intervention. But its key purpose is to explain how the international community, and the UN in particular, can assist the reconstruction of peace in civil war-torn lands^ (p. 4). Doyle and Sambanis are well-placed to write such a book. Doyle, a Professor of International Affairs, Law, and Politics at Columbia University, was formerly Assistant Secretary-General and Special Adviser to Secretary-General Kofi Annan from 2001–2003. Nicholas Sambanis, who formerly conducted research for the World Bank, is an Associate Professor of Political Science at Yale, and has a background in political economy. The book is an expansion of the argument the two scholars made in their seminal 2000 article in the American Political Science Review, BInternational Peacebuilding: A Theoretical and Quantitative Analysis.^ In the article, after building a new and now widely-used cross-sectional dataset of all civil wars since 1944, they made a convincing statistical case that peacebuilding by the United Nations has led to longer-term peace, despite the well-known cases of failure, and despite the fact that the UN is often saddled with the most difficult conflicts. Peacebuilding is defined as Ban attempt, after a peace has been negotiated or imposed, to address the sources of current hostility and build local capacities for Rev Int Org (2006) 1: 401–403 DOI 10.1007/s11558-006-0365-9