The paper traces some possible trajectories of aggressive behaviour in children and adolescents. It distinguishes three contributing factors: 1. Disturbance or Disorder; 2. Deficit and Neglect; and 3. Deviance. Therapeutic technique may need adjusting depending on which factor is dominant at any moment. Two dimensions which seem to run through these categories are first, the question of which type of violence is occurring - that is, the motivation and emotion which accompany the violence; the second question is whose violence: that is, when we study the inner world of aggressive children we discover vast differences in the relationships between the self and the internal objects or representational figures of other people. These two questions will be raised whenever we try to treat these children or adolescents.