The demography of armed conflict is an emerging field among demographers and peace researchers alike. The articles in this special issue treat demography as both a cause and a consequence of armed conflict, and they carry important policy implications. A study of German-allied countries during World War II addresses the role of refugees and territorial loss in paving the way for genocide. Other articles focusing on the demographic causes of conflict discuss highly contentious issues of whether economic and social inequality, high population pressure on natural resources, and youth bulges and limited migration opportunities can lead to different forms of armed conflict and state failure. The articles on demographic responses to armed conflict analyze the destructiveness of pre-industrial warfare, differences in short- and long-term mortality trends after armed conflict, and migratory responses in war. Another set of articles on demographic responses to war is published simultaneously in the European Journal of Population.