As a research topic, global inequalities have only been explicitly present in mainstream academic debates since the beginning of the twenty-first century. To be sure, in the 1970s, social science debates addressed the international division of labor, center–periphery dependencies, imperialism and the world-economy—and thus implicitly global inequalities. However, they took place in parallel with and independent of studies of income and educational inequality which focused almost exclusively on national contexts. It was not until the gap between rich and poor widened in many countries of the Global North, especially in the United States and Great Britain in the 1980s, that global inequalities became the new buzzword under which the world-economy was addressed together with structural inequalities.

At first, debates largely revolved around World Bank findings assessing the relationship between inequality and economic growth in the previous decades. Whether they concluded that “growth is good for the poor” (Dollar and Kraay 2002) or that “inequality is bad for the poor” (Ravallion 2005), they primarily focused on poverty as the decisive issue in poor countries and the one that needed to be addressed first. The World Bank initially argued that mean incomes between countries were converging and that global inequalities were declining. Soon, mounting evidence of a steep increase in the income ratio between the world's richest and the world's poorest individuals, alongside ever more data on rising inequalities within the largest and fastest-growing economies of China and India, overshadowed these claims. By the time Thomas Piketty published Capital in the Twenty-First Century (2013) and Oxfam first reported that the richest 1 percent now owned more wealth than the rest of the planet (Oxfam 2016), global inequalities had become firmly established as both a research topic and a focus of media attention. Yet, by that time, world-systems analysis had dealt with global inequalities for more than forty years—using a more complex and differentiated terminology and a more encompassing historical perspective while anticipating many of the recent arguments and even predicting several country trajectories by a long shot.