Chicago school of economics
In his 1964 book "Human capital theories" Becker introduced the economic concept of human capital. This book is now a classic in economy research and Becker went on to become a defining proponent of the Chicago school of economics. The book was republished in 1975 and 1993. Becker considered labor economics to be part of capital theory. He mused that "economists and plan-makers have fully agreed with the concept of investing on human beings".