Aage Sorensen was an influential intellectual presence who was one of the world's leading authorities on social stratification and the sociology of education. His research sought to understand the structures, dynamics and mechanisms that underlie inequalities in industrial societies by focusing on how individuals' attainments are shaped by characteristics of a society's or organization's opportunity structure, on the one hand, and individuals' education, experience and other human capital resources, on the other. He emphasized inequalities associated with education and schooling, class, and stratification outcomes such as income and occupational status. Within these general foci, he tackled the study of phenomena as diverse as rates of learning in elementary school reading groups and promotion patterns in large industrial corporations. The chapters of this volume illustrate some of the major themes that characterized Aage's research; these topics are also likely to constitute important concerns for future efforts to understand structured social inequality in society. These themes include: the development of explicit dynamic models to account for observed patterns of education, career, and labor market outcomes; aspects of educational inequality such as school effects and learning opportunities; issues related to intragenerational mobility and careers; and the role of rents in generating structural inequality.