This paper examines the implications of skill-biased technological change (SBTC) on the demand for less skilled workers in developed countries. The authors argue that SBTC, rather than increased trade with developing countries, is the primary cause of the decline in the relative wages and employment of less skilled workers in the US and other developed nations over the past two decades. They propose two main reasons for this: first, the pervasive nature of SBTC, which implies that it occurs simultaneously in most developed countries, and second, the potential for SBTC to significantly affect relative wages due to its sector-neutral nature. The authors test these implications using data from 10 OECD countries, finding strong evidence of within-industry shifts away from less skilled workers towards skilled workers, despite rising or stable relative wages. They also find that these shifts were concentrated in the same manufacturing industries across different countries, particularly in sectors associated with the spread of microprocessor technology, such as electrical machinery, machinery (including computers), and printing and publishing. These industries accounted for 40% of the within-industry increase in the relative demand for skills. The paper further discusses the implications of SBTC in a Heckscher-Ohlin (H-O) model, showing that while SBTC does not affect wages in small open economies, it can do so in integrated world economies. The authors conclude that the widespread adoption of SBTC across developed countries provides a consistent explanation for the increased skill premium and within-industry skill upgrading observed in these economies.This paper examines the implications of skill-biased technological change (SBTC) on the demand for less skilled workers in developed countries. The authors argue that SBTC, rather than increased trade with developing countries, is the primary cause of the decline in the relative wages and employment of less skilled workers in the US and other developed nations over the past two decades. They propose two main reasons for this: first, the pervasive nature of SBTC, which implies that it occurs simultaneously in most developed countries, and second, the potential for SBTC to significantly affect relative wages due to its sector-neutral nature. The authors test these implications using data from 10 OECD countries, finding strong evidence of within-industry shifts away from less skilled workers towards skilled workers, despite rising or stable relative wages. They also find that these shifts were concentrated in the same manufacturing industries across different countries, particularly in sectors associated with the spread of microprocessor technology, such as electrical machinery, machinery (including computers), and printing and publishing. These industries accounted for 40% of the within-industry increase in the relative demand for skills. The paper further discusses the implications of SBTC in a Heckscher-Ohlin (H-O) model, showing that while SBTC does not affect wages in small open economies, it can do so in integrated world economies. The authors conclude that the widespread adoption of SBTC across developed countries provides a consistent explanation for the increased skill premium and within-industry skill upgrading observed in these economies.