In Germany, studies on "the dark figure"—an estimation of the number of unreported or undiscovered crimes—have recently been made part of large-scale research programs, such as the First and Second Periodical Report on Crime and Crime Control (2001–6), the Victimization of Survey Module (2008–10), and the Barometer of Security in Germany (2010–13). The need for concrete action in our data-driven society, motivated by a desire to survey a population to its absolute core, activated a nebulous zone beyond "real numbers." These data, generated within the bounds of policy and science, were to grant efforts toward prevention and early intervention a new foundation. A similar public research interest advanced in medicine too: new services, such as those for dissociative personality disorders, addicts, or pedophiliac tendencies, are introduced and justified with reference to an unknown dark figure. The dark figure is party to the classic problems of statistical data collection. This project, concerning the historical epistemology of the dark figure, investigated the ensemble of agencies, techniques, and practices—its various institutional and administrative mechanisms, acting within a field of foreboding, and nescience. In order to gain knowledge not readily accessible to medical institutions or to the state, and to enhance their ability to survey and protect the social body, complex and highly fragile networks had to be established—networks, which require detailed study.