For the members of the cohorts born between 1945 and 1965, the transition from the educational system to the labour market and from social dependence to social independence has changed. This was the case in the United States, The Netherlands, West Germany, and the United Kingdom. The employed between the ages of 15 and 24 make the transition from education to work increasingly later in life in The Netherlands and West Germany. In contrast, this change occurs increasingly earlier in life in the USA, and for the UK at first this change occurs increasingly later and from the 1958 birth cohort it occurs increasingly earlier in life. Furthermore, we conclude that the transition from social dependence to social independence, measured as the number of women who give birth before the age of 25, occurs increasingly later in life in all four countries. In this article four theses are used to explain these changes: the first concerns the size of cohorts, the second centres on the pattern of generations, and the third and fourth involve post-adolescence and individualization. Predictions derived from these theses are tested against empirical data drawn from the United States, The Netherlands, West Germany, and the United Kingdom. Changes are best predicted by the thesis centring on the pattern of generations.