This essay by Daron Acemoglu explores the impact of technical change on wage inequality. It argues that technical change has been skill-biased over the past sixty years, with a recent acceleration in skill bias contributing to increased inequality. The essay contrasts the nineteenth century, characterized by skill-replacing technologies driven by an increase in unskilled labor, with the twentieth century, marked by skill-biased technologies driven by a rapid increase in skilled labor. The author suggests that the recent acceleration in skill bias is a response to the growing supply of skills in recent decades. The essay also discusses the theoretical framework of skill premia and the empirical trends in wage inequality, highlighting the need for further research on the differential behavior of residual inequality and the cross-country differences in wage inequality.This essay by Daron Acemoglu explores the impact of technical change on wage inequality. It argues that technical change has been skill-biased over the past sixty years, with a recent acceleration in skill bias contributing to increased inequality. The essay contrasts the nineteenth century, characterized by skill-replacing technologies driven by an increase in unskilled labor, with the twentieth century, marked by skill-biased technologies driven by a rapid increase in skilled labor. The author suggests that the recent acceleration in skill bias is a response to the growing supply of skills in recent decades. The essay also discusses the theoretical framework of skill premia and the empirical trends in wage inequality, highlighting the need for further research on the differential behavior of residual inequality and the cross-country differences in wage inequality.