This chapter introduces the space of inquiry that opens up at the intersection of security and mobility. It begins with briefly setting the stage of the security/mobility dynamic, after which a conceptual exploration follows. Security is regarded as a discourse revolving around threat. Distinct about security today is it being premised on openness which encourages intervention upon and thus regulation of mobility. Mobility is regarded as socially produced motion and concerns the ways in which the fact of displacement is made possible. Attention is then directed at the productive effects of both concepts and their interaction: they bring about particular relations of power, thereby privileging certain forms of security and mobility. The introductory chapter ends with an overview of the structure of the book and the individual chapters.