Most theories trying to explain social inequalities, their persistence, and their reproduction in the contemporary world presume, just as their commonsensical analogues in Western popular media and politics, that the capitalist transformation includes a radical break with the past. This volume challenges this scholarly common sense by tracing how historically older forms of social inequality are transformed but persist in the present to shape the social structure of contemporary societies. This chapter outlines the theoretical approach applied by all authors of this edited volume. It introduces and discusses the main theoretical concepts: social ontology, socioculture, and social inequality. We draw on established theories of sociology and philosophy, but link them to discussions in anthropology and area studies, and in societies of the global South.