Alvin Harvey Hansen was an American economist. Taught at the University of Minnesota from 1919 to 1937 and at Harvard from 1937-1960. He worked for the Economic State Department in Washington from 1934-35, and was special adviser to the Federal Reserve System between 1940 and 1945. His published work includes Cycles of Prosperity and Depression (1921), Business Cycle Theory (1927), Fiscal Policy and Business Cycles (1941), America’s Role in the World Economy (1945), Monetary Theory and Fiscal Policy (1949), Business Cycles and National Income (1951), A Guide to Keynes (1953), The American Economy (1957), Economic Issues of the 1960s(1965), The Dollar and the International Monetary System (1965). Developed the secular stagnation hypothesis which suggested that interest rates could in times of severe depression not fall low enough to induce investment.