Global science expansion and the ‘skills premium’ in labor markets have been extensively discussed in the literature on the global knowledge economy, yet the focus on, broadly-speaking, knowledge-related personnel as a key factor is surprisingly absent. This article draws on UIS and OECD data on research and development personnel for the period 1980 to 2015 for up to N = 82 countries to gauge cross-national trends and to test a wide range of educational, economic, political and institutional determinants of general (...) expansion as well as expansion by specific sectors and country groups. Findings show that, worldwide, the number of personnel involved in the creation of novel and original knowledge has risen dramatically in the past three decades, across sectors, with only a few countries reporting decrease. Educational and economic predictors show strong effects. Expansion is also strongest in those countries embedded in global institutional networks, yet regardless of a democratic polity. I discuss the emergence of ‘knowledge work’ as a mass-scale and worldwide phenomenon and map out consequences for the analysis of such a profound transformation, which involves both an educated workforce and the strong role of the state. (shrink)