This volume brings together former students, colleagues, and others influenced by the sociological scholarship of Archibald O. Haller to celebrate Haller's many contributions to theory and research on social stratification and mobility. All of the chapters respond to Haller's programmatic agenda for stratification research: 'A full program aimed at understanding stratification requires: first, that we know what stratification structures consist of and how they may vary; second, that we identify the individual and collective consequences of the different states and rates of change of such structures; and, third, seeing that some degree of stratification seems to be present everywhere, that we identify the factors that make stratification structures change'. The contributors to this Festschrift address such topics as the changing nature of stratification regimes, the enduring significance of class analysis, the stratifying dimensions of race, ethnicity, and gender, and the interplay between educational systems and labor market outcomes. Many of the chapters adopt an explicitly cross-societal comparative perspective on processes and consequences of social stratification. The volume offers both conceptually and empirically important new analyses of the shape of social stratification.