In a world where oil-rich states are more likely to start war than their oil-dependent counterparts, it's surprising how little attention is still paid to these so-called petrostates. These states' wealth props up the global arms trade, provides diplomatic leverage, and allows them to support violent and nonviolent proxies. In Oil, the State, and War, Emma Ashford explores the many potential links between domestic oil production and foreign policy behavior and how oil production influences global politics. Not all petrostates have the same characteristics or capabilities. To help us conceptualize these differences, Ashford creates an original classification of three types of petrostates: oil-dependent states (those weakened by the resource curse), oil-wealthy states (those made rich by oil exports), and super-producer states (those that form the backbone of the global oil market). Through a combination of case studies and analysis, she illustrates how oil shapes petrostates' behavior, filling a major gap in our understanding of the international implications of oil wealth. As the oil market undergoes a period of rapid change, Oil, the State, and War sheds light on the diversity of petrostates and how they shape international affairs.