Chapter 2 provides the theoretical framework for the book's empirical analysis and clarifies a number of theoretical and conceptual tools that are central to this book's objectives and contributions. Power and security are two such concepts, and the chapter begins by clarifying the conceptualisation of power outlined by Michel Foucault that is adopted in this study by elaborating upon one of his ideas: power/knowledge. From here the chapter hones in on the "third modality" of power, that of governmentality, to demonstrate how this functions across society and the role that the security dispositif plays in allowing this form of power to function. Prior to embarking on the empirical analysis, this chapter's final section ties together the work on power, governance and security with established work on both "epistemic communities" and "security professionals". I elaborate on these theorisations to link the productive functioning of power with the role particular "privileged" experts play within the dispositif to give meaning to the phenomenon of security, sediment certain understandings, prioritise particular responses and foreclose alternative thinking. It is in this final section where I most explicitly make the argument for the need to conduct constructivist research into private security industry discourse.