The answer to the question in the title is: A lot. In this essay, I argue that the history of macroeconomics during the 20th century can be divided in three epochs: Pre 1940. A period of exploration, where macroeconomics was not macroeconomics yet, but monetary theory on one side, business cycle...

The intellectual response to the Great Depression is often portrayed as a battle between the ideas of Friedrich Hayek and John Maynard Keynes. Yet both the Austrian and the Keynesian interpretations of the Depression were incomplete. Austrians could explain how a country might get into a...

This paper examines the influence of Irving Fisher's writings on Milton Friedman's work in monetary economics. We focus first on Fisher's influences in monetary theory (the quantity theory of money, the Fisher effect, Gibson's Paradox, the monetary theory of business cycles, and the Phillips...

This paper distinguishes two kinds of Endogenous Business Cycle models; EBC1 models, which display dynamic indeterminacy, and EBC2 models, which display steady-state indeterminacy. Both strands of the literature have their origins in the sunspot literature that developed at the University of...

We propose and evaluate a technique for instrumental variables estimation of linear models with conditional heteroskedasticity. The technique uses approximating parametric models for the projection of right hand side variables onto the instrument space, and for conditional heteroskedasticity and...

This Economica Coase Lecture reviews research that has revolutionized the field of international trade and foreign direct investment. It explains the motivation behind the development of new analytical frameworks, the nature of these frameworks, and the empirical studies that sprouted from them

Ensuring that a firm has sufficient liquidity to finance valuable projects that occur in the future is at the heart of the practice of financial management. Yet, while discussion of these issues goes back at least to Keynes (1936), a substantial literature on the ways in which firms manage...

On December 1933, John Maynard Keyes published an open letter to President Roosevelt, where he wrote: “The recent gyrations of the dollar have looked to me more like a gold standard on the booze than the ideal managed currency of my dreams.” In this paper I use high frequency data to...

On December 31 1933, The New York Times published an open letter from John Maynard Keynes to President Franklin D. Roosevelt. In it Keynes encouraged FDR to expand public works through government borrowing. He also criticized FDR's exchange rate policy, and argued that there was a need for lower...

In the 1920s, Irving Fisher extended his previous work on the Quantity Theory to describe, through an early version of the Phillips Curve, how changes in the money stock could be associated with cyclical movements in output, employment, and inflation. At the same time, Holbrook Working designed...