In the Cambridge Study of Delinquent Development, 411 London males have been followed up from age 8 to age 32. Offending was only one element of a general syndrome of antisocial behaviour, which showed significant continuity from childhood to adulthood. The most important childhood (age 8–11) predictors of offending up to age 32 were: socio-economic deprivation, poor parenting, family deviance, school problems, hyperactivity-impulsivity-attention deficit, and antisocial child behaviour. A theory was proposed to explain these results, including criminal motivation, internalized beliefs about offending, and rational decision-making. It was concluded that the most hopeful methods of preventing offending were behavioural parent training and pre-school intellectual enrichment programmes.