Mapping the Germans explores the development of statistical science and cartography in Germany between the beginning of the nineteenth century and the start of World War One, examining their impact on the German national identity. It asks how spatially-specific knowledge about the nation was constructed, showing the contested and difficult nature of objectifying this frustratingly elastic concept. Ideology and politics were not themselves capable ofproviding satisfactory answers to questions about the geography and membership of the nation; rather, technology also played a key role in this process, helping to produce the scientific authority needed to make the resulting maps and statistics realistic. In this sense, Mapping the Germans is about how theabstract idea of the nation was transformed into a something that seemed objectively measurable and politically manageable.Jason Hansen also examines the birth of radical nationalism in central Europe, advancing the novel argument that it was changes to the vision of nationality rather than economic anxieties or ideological shifts that radicalized nationalist practice at the close of the nineteenth century. Numbers and maps enabled activists to see nationality in local and spatially-specific ways, enabling them to make strategic decisions about where to best direct their resources. In essence, they transformednationality into something that was actionable, that ordinary people could take real actions to influence.