Many approaches to understanding social stratification, whether they focus on class or status, ethnicity or gender, assume a continuous present. They seek to identify who gains and who loses, who is included and who excluded, by core social practices at a given moment in time. Age cohorts can be isolated and identified in this way too. Their relative size, situation, cultural resources and historical experience lay the basis for generational identities and projects. Thomas Jefferson observed that each generation was a new country. As individuals bid for self-expression, recognition, responsibility and rewards they will appeal to, or help to constitute, a generational character and project. On the other hand, each generation is bound to its predecessors and successors by the life course, and locked into a cycle of inter-generational dependence applying to the young and the old alike.