This chapter sets the scene for the subsequent philosophical discussions by surveying a number of biological interventions that have been used, or might in the future be used, for the purposes of crime prevention. These interventions are pharmaceutical interventions intended to suppress libido, treat substance abuse or attention deficit-hyperactivity disorder (ADHD), or modulate serotonin activity; nutritional interventions; and electrical and magnetic brain stimulation. Where applicable, we briefly comment on the historical use of these interventions, and in each case we discuss the evidence that they are effective, or might become so with further refinement. The chapter concludes with a comment on some potentially significant differences between the varieties of intervention that we canvass.