This chapter examines two major, related questions: how effective is law in preventing criminal behavior in the general society and in preventing repeat offending by offenders after they have been arrested, prosecuted, and punished? and how effective is law in dealing with consensual behaviors that are deemed criminal largely because they offend our society's sense of moral order? Socialization and informal social control certainly characterize modern societies like the United States. Incapacitation in criminal justice occurs when offenders are incarcerated and cannot commit crimes in the outside society. The chapter distinguishes the several types of deterrence and describes the difference between expressive crimes and instrumental crimes. It assesses the size of the incapacitation effect and the cost-effectiveness of mass incarceration. The chapter summarizes the philosophical and social science questions in regard to laws against consensual crime. White-collar crime, illegal behavior committed by individuals or organizations during the course of legitimate business or professional activity, is a serious problem.