MOST PREDATORY street criminals--people who hit, rape, rob, burglarize, deal drugs, and murder--are teenage or young adult males. Of the nation's over four million persons under correctional supervision (in prison, in jail, on probation, or on parole), a majority are males who had their first brush with the law before they were old enough to drink. In a major prisoner self report survey conducted in 1990, 57 percent of the respondents said they were under eighteen at the time of their first arrest; 40 percent said they were under eighteen the first time they were convicted; and 70 percent said they had committed three or more serious crimes before their nineteenth birthdays. The median (as well as the mean) age at which they began their criminal careers was fourteen.