Work has always been and remains a powerful integrator in society. It gives places, duties and rights and distributes the individuals on a scale of social prestige. However, on a long period the sense of work has changed. It gets more diversified and it is now a matter for high expectations, of different kinds – instrumental, social, symbolic – that do not replace each other. In post-industrial societies, work and identities are still strongly intertwined despite a progressive distance vis-à-vis work (if work is considered as a value per se). Work remains a social integrator but it has no longer a hegemonic value. There is a generational component in these changes, both in the subjective meaning of work and in its objective conditions (status, trajectories, security…). Do such generational differentiations unavoidably lead to fractures in social cohesion? That is the key question of this book.