World-systems Theory, pioneered by sociologist Immanuel Wallerstein, is a macro-sociological theoretical framework that emphasises the interconnections and interdependence among countries based on the historical expansion and ongoing dynamics of a single, global capitalist world-economy. This theory posits that the world is not a collection of independent national economies but rather a complex, integrated system characterised by a hierarchical division of labor and power relations among three main categories of countries: core countries (dominant, wealthy, industrialised nations controlling global finance and high-profit production), semi-peripheral countries (intermediate, with some industrialisation but still dependent), and peripheral countries (less developed, exploited for raw materials and cheap labor). World-systems Theory analyses how this global structure shapes the economic development, social structures, and political dynamics of individual nations, perpetuating patterns of global inequality and dependence, and highlighting the historical roots of global disparities and the ongoing power dynamics that maintain them. It critiques modernisation theory for its nation-state focus.