This theme is concerned with a variety of behaviours and activities that can potentially lead either to unfavourable or indeed enhanced outcomes for young people. Such behaviours and activities under the headings of risky behaviours; truancy and disengagement; youth crime and positive activities. Of course many young people engage in clusters of these activities and interaction effects will potentially be crucially important. The work under this theme will relate strongly to the research programme of the other centre being commissioned on understanding behaviour change. The findings from CAYT on risky behaviours and positive activities will both inform and be informed by the more experimental based work likely to be undertaken by that centre.