Section 53 offenders are children and young people between the ages of 10 and 17 inclusive who commit grave crimes and are sentenced to be detained, some indeterminately, under Section 53 of the Children and Young Persons Act 1933. They are a small but singular group of offenders, currently numbering around 780, whose ages range from 11 to 63 years. In this publication, Dr Boswell presents her research findings into the characteristics of this group, looking particularly at the prevalence of abuse and loss in their backgrounds. She additionally considers the exercise of legal, judicial, executive and probation/social service discretion in the sentancing and custodial progressions to which these offenders are subject. The knowledge and skill base required for effective practice in this specialised field is identified and pointers for crime prevention, criminal justice policy, custodial career management and the enhancement of public understanding are provided.