By the time of writing, Oxford University Press has already published some 530+ handbooks – this one covering all 67 the United Nations peacekeeping operations launched in the period 1948 to 2013. At a time when violent conflict seems to dominate international news unceasingly, it is highly relevant to be reminded of the challenges and limits, but also the achievements and opportunities of UN blue helmets’ operations. Increasingly, police contingents are participating in what have therefore become “blue berets” operations (the many civilian UN missions which fall under the UN Department of Political Affairs, DPA – as opposed to the UN Department of Peacekeeping Operations, DPKO – are not covered in this volume).

In the past, all four editors have contributed various important and well-researched pieces in the wider field of conflict studies. Joachim A. Koops is Dean of Vesalius College at the Vrije Universiteit Brussels and director of the Global Governance Institute (Belgium); Norrie MacQueen is an honorary research fellow at the School of International Relations at the University of St. Andrews (Scotland); Thierry Tardy is a senior analyst at the European Union Institute for Security Studies in Paris (France); and Paul D. Williams is associate professor at the Elliott School of International Affairs at the Gorge Washington University and also an adviser at the International Peace Institute in New York City (USA). The editors not only provide introductions to all parts and sections of the volume, but also contribute articles in their respective fields of expertise (MacQueen on UNSF in West New Guinea, UNYOM in Yemen, as well as UNTAET, UNMISET and UNMIT in East Timor; Koops on ONUGA in Central America, UNMOT in Tajikistan, and UNASOG in the Aouzou Strip; Tardy on UNPROFOR in Croatia, UNPROFOR in Bosnia-Herzogovina, UNPREDEP in Macedonia, and UNMIBH in Bosnia and Herzegovina; and, finally, Williams on UNOSOM I and II in Somalia).

The edited collection is structured in two parts: Following an introduction by the editors, the first five contributions (pp.13-108) set the stage by looking at general trends in peace operations 1947-2013 (Alex J. Bellamy and Paul D. Williams), peacekeeping and the development of international law (Nigel D. White), the UN’s inter-organizational relations in peacekeeping (Joachim A. Koops an Thierry Tardy), peace operations and humanitarian interventions (Thomas G. Weiss) and a critical assessment of peace operations (Paul F. Diehl and Daniel Druckman).

The second part of this collection (pp. 109-864) – UN peace operations 1948 to 2013 – comes in four sections, again each introduced by the editors. In chronological order section one deals with the early experiences in UN peace keeping, 1948-1963 – i.e. those years when Asia and the Middle East were the dominant spaces of the seven UN activities during a period that was heavily influenced by UN Secretary-General Dag Hammarskjöld. Section two on cold war peacekeeping (1964-1987) looks at six missions, ranging from Cyprus to Lebanon, that were constrained by superpower rivalry as well as a growing political and financial crisis at the UN. Section three on post-cold war peacekeeping (1988-1998) details 34 missions – from Afghanistan/Pakistan to Sierra Leone, and including the Balkans and many African countries. Importantly, this period also saw some form of disillusionment about the UN “as a crisis management actor” (p. 261), including failure in Somalia, Bosnia, Angola, and Rwanda. And section four on peacekeeping in the late 20th and early 21st century introduces another twenty cases, from Kosovo to Mali. This period was characterized by the United States’ “war on terror” and the 2008 global financial crisis on the one hand, but also various efforts at a further professionalization of UN peacekeeping.

All chapters follow a similar makeup: Starting with a historical overview on the respective mission’s mandate and activities, the achievements and weaknesses of the missions are discussed. The footnotes offer a rich choice of relevant UN documents – but it is only the very last chapter that demonstrates how these could be linked to the sources from partnering institutions, such as the African Union.

In general, the editors highlight five major challenges of UN peacekeeping: First, often they have suffered “as a result of policies pursued by the organization’s own member states” (p. 7). Second, the institutional structure of the UN “often proved to be inadequate to the rapid deployment and subsequent management of large multidimensional and multinational operations” (ibid.). Third, over time peacekeeping has become more complicated due to more complex conflict structures. Fourth, peacekeepers have not always met the high expectations put into them with regard to the protection of civilians (and the on-going debates about sexual abuse of children and other civilians by UN peacekeepers are a prominent example of this). And, fifth, contemporary peacekeeping is facing debates about its effectiveness and inherent flaws (as captured in terms such as “integrated missions” or “robust peacekeeping”).

Obviously the number of peacekeeping missions has mushroomed since the end of the Cold War. Throughout the decades the UN has managed to remain the main source for international legitimacy to intervene in armed conflicts – though especially in recent years regional organizations have increasingly tried to play a role in their own right, in particular in Africa.

All in all this is a unique, well-written and comprehensive reference book for scholars and practitioners alike.