One straightforward way for a scientist to achieve fame and immortality is to get his name associated with a concept widely used in his science. The late Erik Lundberg meets this qualification by having given name to the “Lundberg lag,” reflecting the time it takes to adjust output to a change in sales. This output lag is found in Lundberg's dissertation, Studies in the Theory of Economic Expansion (1937). What is not so well known is that this hardly readable classic work of the Stockholm School also contains at least three important contributions to the dynamics of economics: the multiplier-accelerator, the Harrod-Domar growth model, and the inflationary gap in a multiperiod setting.

Here I will examine the way in which Studies in the Theory of Economic Expansion can be seen as a complement to John Maynard Keynes's General Theory (1936). The analysis focuses on how Lundberg connects John M. Clark's (1917) investment accelerator with the Keynesian multiplier of efficient demand, using the Lundberg output lag.

William J. Baumol, in a contribution in this volume, is not the first to point to the advantages of Lundberg's dynamic methods. In fact, Joseph Schumpeter (1954, p. 1174), in his History of Economic Analysis, gave credit to Lundberg's thesis in the following way: “it displays the micro- and macrodynamic roots of current Keynesianism much better than did Keynes himself.” This statement raises two questions: First, what is there to be found in Lundberg's Studies but not in the General Theory? Second, why did Lundberg's dissertation fail to achieve international attention?