Semaanurbulbul · CC BY-SA 4.0

Immanuel Wallerstein developed world-systems theory, arguing that capitalism should be understood not nation by nation but as a single interconnected system dividing the globe into a wealthy core, a dependent periphery, and a semi-periphery between them — a framework that reshaped how sociologists and historians analyze global inequality. He led the International Sociological Association and, from Yale, published syndicated commentary on world affairs for over two decades, applying his structural framework to the news as it happened rather than only to history.