This article introduces the themes and arguments of the special issue. While virtually all polities enjoy uncontested international legal sovereignty, there are wide variations in statehood, that is, the monopoly over the means of violence and the ability of the state to make and implement policies. Areas of limited statehood are not, however, ungoverned spaces where anarchy and chaos prevail. The provision of collective goods and services is possible even under extremely adverse conditions of fragile or failed statehood. We specify the conditions under which external efforts at state-building and service provision by state and nonstate actors can achieve their goals. We focus on the extent to which external actors enhance the capacity (statehood) of authority structures in weak states, or directly contribute to the provision of collective goods and services, such as public health, clean environment, social security, and infrastructure. We argue that three factors determine success: legitimacy, task complexity, and institutionalization, including the provision of adequate resources.This special issue begins with the empirical observation that the idealtypical conception of a consolidated state is misleading rather than illuminating. A consolidated state enjoys the privileges of international legal sovereignty, including recognition, the right to enter into treaties, and to join international organizations. It is a full "Westphalian/Vattelian" sovereign: Domestic authority structures are autonomously determined. It exercises effective domestic sovereignty, what we term here statehood, that is, the monopoly over the legitimate use of force and the ability to successfully make, implement, and enforce rules and regulations across all policy arenas within its territory (Krasner 1999;Risse 2011).This ideal typical construct is far removed from the situation that exists in most of the world's polities. Most relevant for this special issue, there are wide variations in statehood. These variations are here to stay and it makes little sense to orient external efforts at capacity-building and service provision toward an ideal of consolidated statehood that only exists in some parts of the world.