The introduction maps out a broad historical framework for the eight essays in Part One of the volume. Drawing on Roderick Beaton’s concept of long-term and contingent “schisms,” the discussion focuses primarily on political ideology and ethno-nationalism as interrelated drivers of conflict underwriting the latent and overt civil wars of the early twentieth century. A further aspect to the civil wars is also presented in the introduction, namely that of racial biology. Although not directly addressed in the volume, this was, it is argued, an important component of Europe’s civil conflicts, framing the mentalité of groups at war with one another. It was one of, if not the, key drivers of early twentieth-century violence as the national community sought to redefine itself as a biological body purified of “foreign” ideological and ethnic elements.