Durable Inequality is a very ambitious work of social theory by one of our foremost sociologists. In many ways, it builds upon the grand master theorists of the nineteenth century through a language of the present. It is like the more structuralist versions of Marx. For Marx, however, class relations and class inequality have different dynamics and different characteristics, depending on historically variable modes of production. For Tilly, inequality refers to relations between paired and unequal categories that have differential access to value- producing resources. And for Tilly, again in contrast to Marx, categorical inequality is perpetuated—is durable—in large measure because of various specified organizational properties and dynamics. There are no contradictions for Tilly, no dynamics of change that are internal to his model or vary by the specific historical conditions that one is attempting to analyze. This is, indeed, surprising for a scholar so identified with historical sociology. In Tilly's formulation, the characteristics and dynamics through which categorical inequality creates durable inequality appears transhistorical. It is not inequality under capitalism that seems to be Tilly's focus, but, rather, a universal theory of inequality across time.