Although prisoners may associate closely with other criminals within jail, many more offenders were introduced to crime outside prison. A deprived social background, a family life disrupted by domestic violence and family members with histories of criminal behaviour can all lead an individual to become involved with crime.  For many young men, prison can become a sanctuary from links with gangs or a chaotic and damaging home life. Once placed within the regulated, disciplined environment of the prison, they can be introduced to the essential skills and educational opportunities that they may have been denied in the outside world.  Prison can give an individual the opportunity to develop the practical and psychological skills they require to escape social alienation. Many prisons in Europe, the UK and the States achieve this objective. US prisons may also operate special units that offer help and protection to offenders who want to leave gangs.  Under-staffing and a poor understanding of inmates’ needs are arguments for reform of the prison system, not arguments against incarceration itself. Where these issues are addressed, rehabilitation programmes have had many successes. Once political prejudices about building and funding rehabilitation oriented prisons are overcome, the benefits of penal supervision will become more accessible.