Sourcing data and analyses from the rigorous Correlates of War Project, this book describes how civil war is defined and categorized and presents data and descriptions for nearly 300 civil wars waged from 1816 to the present. Analyzing trends over time and regions, this work is the definitive source for understanding the phenomenon of civil war, bringing together an explanation of the theoretical premises driving the Correlates of War Project, along with revisions to categories of, and actors in, civil wars that have been made over the years, and data from the Nations, States and Entities civil war dataset.