In this collection we critically examine the crafting of transnational policing. While international police cooperation in the 'war on drugs' is an example of this phenomenon, our scope is much broader. By 'crafting' we invoke the sense of state-crafting, the involvement by international organisations, donor states and agencies in the building and strengthening of state institutions in other countries (typically, perceived by outsiders as 'weak', 'fragile', 'failing' or 'failed'). Such exercises today are often referred to as instances of nation-building or state-building (Fukuyama, 2004; 2006). Such a focus invites consideration of the processes by which these transnational engagements in police-building and police reform occur, and the particular institutional expressions of policing power that result. It also requires that the limits of institutionalist approaches to police-building be considered. Beyond the question of how institutionalism occurs around policing, this collection is also concerned with the selection of policing as an instrument of geo-political strategy. In short, while many see the engagements of countries such as the United States in overseas interventions of different kinds (often, at least initially military-led) as expressions of 'global policing', this collection attempts to capture the increasingly police-led nature of transnational state-crafting (or statebuilding) exercises. As we shall see, it is evident in practices as diverse as humanitarian intervention, peacekeeping, peace enforcement, technical assistance and training, longer-term capacity-building and development assistance, and is prompted or justified by a range of strategic and other objectives.