This book offers a fresh perspective on the early history of macroeconomics, by examining the macro-dynamic models developed from the late 1920s to the late 1940s, and their treatment of economic instability. It first explores the differences and similarities between the early mathematical business cycle models developed by Ragnar Frisch, Michal Kalecki, Jan Tinbergen and others, which were presented at meetings of the Econometric Society and discussed in private correspondence. By doing so, it demonstrates the diversity of models representing economic phenomena and especially economic...