Civil wars are nasty, brutish, and long. Monica Duffy Toft introduces this complex and timely topic. Civil wars are the most common form of large-scale political violence. In the past thirty years, the study of civil wars has been one of the largest growing segments of the international relations field. Their causes are complex, ranging from fights over access to housing, jobs, and arable land or other resources, to political contests over offices, rights, and representation. Because civil wars tend to drag on, motives and relevant actors shift. Groups form, collapse, coalesce, align andrealign, and then fight amongst themselves. Governments themselves change through elections, coups, military defeats, or revolutions. Understanding the origins of civil wars and their trajectories therefore demands some appreciation of the economic, political, social, cultural, and geographic order ofsocieties. If there is one factor that best predicts why a civil war erupts, it is a prior civil war. Th
