The research was prompted by the opinion of some analysts that the increasing numbers of misconduct and serious disturbances result from the emergence of new offenders who are younger and more violent than previous generations of Federal inmates. The analyses of data on a cross-section of Federal inmates failed to reveal consistent evidence that such new offenders are the reason for changes in misconduct rates. However, when the analyses were limited only to the recent admissions cohort and focused on the early years of incarceration, some evidence appeared to support the perception among BOP personnel that a different type of inmate is arriving in the Federal prison system. However, a number of BOP programs are specifically designed to address criminal lifestyles and patterns of thinking among inmates. Thus, the residential drug treatment programs in Federal prisons place major emphasis on the choices that inmates have made in using drugs or committing crimes. An important component of these programs is exploring how inmates have used aggression and coercion to achieve their goals, examining the ways in which this behavior can and does harm others, and exploring other available approaches and lifestyles. A study of 462 graduates of such a program indicates that this approach can be successful. Tables and 36 references