 Rothbard holds the interventionist policies of the Herbert Hoover administration responsible for magnifying the duration, breadth, and intensity of the Great Depression.Rothbard explains the Austrian theory of the business cycle, which holds that government manipulation of the money supply sets the stage for the familiar "boom-bust" phases of the modern market.He then details the inflationary policies of the Federal Reserve from 1921 to 1929 as evidence that the depression was essentially caused not by speculation, but by government and central bank interference in the market.