Though private military and security companies (PMSCs) have been addressed extensively in the literature, little research has been done on the contractors themselves, leaving us in the dark as to who these individuals are. In this article, we focus on the critical case of the United States armed services and argue that two broad developments have been converging that both point to the need for new, microlevel sociological research on the people who are involved in the global PMSC industry. To this end, we first draw from an extensive political science literature to illustrate the rise of the PMSCs and concomitant evolution of the security sector, while noting a new trend that points to the need for moving from the macrosocial to the microsocial level of inquiry. Second, we indicate the challenges contractors pose to the sociological paradigm of military professionalism: These suggest a need to move from the mesosocial to the microsocial level of inquiry. We conclude by reviewing the existing research on the demographics of the sector and then indicating the troubling gaps in our current understanding of this critical sector of the national security apparatus.