<P> World - systems theory (also known as world - systems analysis or the world - systems perspective), is a multidisciplinary, macro-scale approach to world history and social change which emphasizes the world - system (and not nation states) as the primary (but not exclusive) unit of social analysis . </P> <P> "World - system" refers to the inter-regional and transnational division of labor, which divides the world into core countries, semi-periphery countries, and the periphery countries . Core countries focus on higher skill, capital - intensive production, and the rest of the world focuses on low - skill, labor - intensive production and extraction of raw materials . This constantly reinforces the dominance of the core countries . Nonetheless, the system has dynamic characteristics, in part as a result of revolutions in transport technology, and individual states can gain or lose their core (semi-periphery, periphery) status over time . This structure is unified by the division of labour . It is a world - economy rooted in a capitalist economy . For a time, certain countries become the world hegemon; during the last few centuries, as the world - system has extended geographically and intensified economically, this status has passed from the Netherlands, to the United Kingdom and (most recently) to the United States . </P> <P> Immanuel Wallerstein has developed the best - known version of world - systems analysis, beginning in the 1970s . Wallerstein traces the rise of the capitalist world - economy from the "long" 16th century (c. 1450--1640). The rise of capitalism, in his view, was an accidental outcome of the protracted crisis of feudalism (c. 1290--1450). Europe (the West) used its advantages and gained control over most of the world economy and presided over the development and spread of industrialization and capitalist economy, indirectly resulting in unequal development . </P> <P> Though other commentators refer to Wallerstein's project as world - systems "theory", he consistently rejects that term . For Wallerstein, world - systems analysis is a mode of analysis that aims to transcend the structures of knowledge inherited from the 19th century, especially the definition of capitalism, the divisions within the social sciences, and those between the social sciences and history . For Wallerstein, then, world - systems analysis is a "knowledge movement" that seeks to discern the "totality of what has been paraded under the labels of the...human sciences and indeed well beyond". "We must invent a new language," Wallerstein insists, to transcend the illusions of the "three supposedly distinctive arenas" of society, economy and politics . The trinitarian structure of knowledge is grounded in another, even grander, modernist architecture, the distinction of biophysical worlds (including those within bodies) from social ones: "One question, therefore, is whether we will be able to justify something called social science in the twenty - first century as a separate sphere of knowledge ." Many other scholars have contributed significant work in this "knowledge movement". </P>

Who developed the world systems theory which explains how global stratification developed