Approximately one third of child sexual abuse is carried out by children and young people themselves. There is growing public awareness of this issue, as well as recognition among professionals that this is a key concern in the safeguarding of children. Working with children and young people who have displayed harmful sexual behaviour raises challenging dilemmas around balancing risk management with the need to provide opportunities for social and emotional development. Strong feelings of anxiety may be present among professionals and considerable levels of shame and stigmatisation are often experienced by these children and their families. Allardyce and Yates focus on the importance of recognising that young people who have displayed harmful sexual behaviour are children first and foremost. They outline an individualised, trauma informed and systemic approach to working with these children and their families. In particular they suggest an approach that moves away from an exclusive focus on the psychology of the individual child towards a wider contextual understanding of the child and the meanings of their behaviour within their family and environment. The authors provide an overview of up-to-date empirical and theoretical knowledge about children and young people who have displayed harmful sexual behaviour to produce a practical text that is suitable for students and professionals working in child care settings.