New technologies allow the isolation of specific genes and the measurement of neurological functions. The human body contains approximately 74 trillion genes, which are chemical roadmaps for the human organism. Few studies have focused on the biopsychosocial interactions of crime, violence, and drug abuse; Farrington’s 1994 report concluded that the interaction effects among variables decrease with the offender’s age and suggest that antisocial behavior becomes more ingrained over time. Studies by Wadsworth (1976); Christiansen (1977); Raine and Venables (1981); Cloninger and Gottesman (1987); Moffit (1990); Raine, Brennan, and Mednick (1994); Mednick and Kandal (1988); and Lewis and others (1988) provide some indication of the interaction effects between genetics, neurology, and criminal behavior. The four major biopsychosocial theories of criminal behavior are Eysenck’s theory of criminal behavior, Mednick’s biosocial theory of criminal behavior, Buikheysen’s biosocial theory of crime and juvenile delinquency, and Moffitt’s life-course-persistent offender theory. Genetic studies have focused on compulsion and drug abuse, body type and gender, and genetic and behavioral risk factors of violence. Brain imaging has used the techniques of positron emission tomography and single photon emitted computed tomography. More research is needed. 17 references