Abstract
The first part of this article deals with the uses of the concept of generation in the historical and social sciences. Following Mannheim’s approach, generations are conceived as produced by the differential impact of socio-cultural change on different age cohorts. The concept of “crucial event” in the biography of individuals is discussed in the light of developmental social psychology. Specific attention is devoted to the methodological problems in researching generations. The second part is devoted to the literature on political generations and to answering the question of whether and how 1989 and 11 September 2001 are producing generational phenomena in contemporary advanced countries.