J. Schumpeter is a key figure, even a seminal one, on technological innovation. Most economists who study technological innovation refer to Schumpeter and his pioneering role in introducing innovation into economic studies. However, despite having brought forth the concept of innovation in economic theory, Schumpeter provided few if any analyses of the process of innovation itself. This paper suggests that the origin of systematic studies on technological innovation owes its existence to the economist W. Rupert Maclaurin from MIT. In the 1940s and 1950s, Maclaurin developed Schumpeter's ideas, analyzing technological innovation as a process composed of several stages or steps, and proposed a theory of technological innovation, later called the linear model of innovation. The paper also argues that Maclaurin constructed one of the first taxonomies for measuring technological innovation.