Joseph Schumpeter
Read this biographical article about Joseph Schumpeter. It gives some interesting context to his innovations in economic thought, which were largely eclipsed by the rise of Keynesian economics.
Work
Entrepreneurship
The concept of entrepreneurship cannot be fully understood without Schumpeter's contributions, being probably the first scholar to develop its theories. Schumpeter argued that the innovation and technological change of a nation comes from the entrepreneurs, or wild spirits. He came up with the German word Unternehmergeist, meaning "entrepreneur-spirit". He believed that these individuals are the ones who make things work in the economy of the country.
Later, in the United States, he pointed out that the ones who really move the innovation and economy are the big companies which have the resources and capital to invest in research and development. One can, however, see both arguments as being complementary.
In Schumpeter's theory, Walrasian equilibrium is not adequate to capture the key mechanisms of economic development. Schumpeter also thought that the institution enabling the entrepreneur to purchase the resources needed to realize his or her vision was a well-developed capitalist financial system, including a whole range of institutions for granting credit.