The text introduces five case studies on war and the military in the USSR and Yugoslavia in historical perspective. It argues that the armed forces were at the core of socialist statehood and that their role and their change in late socialism and post-Communism are thus far understudied. Discussing the similarities as well as the differences between the Soviet, the Russian, and the Yugoslav case, the introduction seeks new explanations for war and military violence in these countries. Rather than pointing exclusively to ethnic mobilization and nationalism, it views the transformation and collapse of the Communist party-state and its army as a precondition for violence and civil war. It places these cases using innovative methodological approaches to the research on physical violence, war, and military. These studies explore the experience and the representation of violence, army service, combat, and war in late socialism and scrutinize individual actors and their behavior within violent spaces. In retrospect the emerging wars in the post-Soviet space – from Chechnya to the Donbas – and in Yugoslavia are at least as crucial for the region as Gorbachev’s reforms. They help to better understand the conflicts of the present.