Alvin Hansen became a professor at Harvard in 1937. Hansen famous "secular stagnation" thesis came out the next year, in his presidential address to the AEA, with the harrowing vision of an economy trapped permanently in a slump of low population growth and low investment.. At first suspicious of Keynes's General Theory when it first came out, Hansen soon converted c.1938 and became its chief champion. His 1941 treatise re-articulated American business cycle history in terms of Keynesian theory.