The bulletin first reviews the historical changes that have occurred in the processing of juveniles and young adults under the juvenile and adult justice systems, as well as hybrid systems whose procedures are combinations of adult and juvenile justice procedures. The focus is on the pendulum swings between the emphasis on rehabilitation and punishment, as well as the current emphasis on evidence-based practices. The latter practices focus on public safety through individualized risk/needs assessments that yield sentencing and corrections with both appropriate accountability/restraints and rehabilitative services that effectively address identified criminogenic needs. The Study Group concludes that the research evidence, particularly from developmental neuroscience, suggests that young adults (ages 18-24) are more similar to juvenile than to adults in many respects. This conclusion is reflected in the Study Group's six policy recommendations. First, the effects of raising the minimum age for adult court to age 21 or 24 should be considered. Second, a promising forward-looking model for older serious and violent adolescent offenders is the British T2A initiative, which is described in this bulletin. Third, there could be a "youth discount" or "immaturity discount" for young adult offenders, which takes into account lesser culpability and diminished responsibility. Fourth, there should be risk/needs assessment and screening of young adult offenders. Fifth, there should be evidence-based programs for young adult offenders in the community and after release. Sixth, other useful programs reduce the opportunities for offending. Approximately 125 references