In the WSJ, from a George Mason prof, how Germany came out of the post WW2 economic slump:
Fortunately for ordinary Germans, Erhard—who became director of the economic administration for the U.K.-U.S. occupation Bizone in April 1948—thought otherwise. A currency reform that he helped to design was slated to replace the feeble old Reichsmark with the new Deutsche mark in all three Western zones on June 20. Without approval from the Allied military command, Erhard used the occasion to issue a sweeping decree abolishing most of the price controls and rationing directives. He later told friends that the American commander, Gen. Lucius Clay, phoned him when he heard about the decree and said: “Professor Erhard, my advisers tell me that you are making a big mistake.” Erhard replied, “So my advisers also tell me.”
It was not a big mistake. In the following weeks Erhard removed most of the Bizone’s remaining price controls, wage controls, allocation edicts and rationing directives. The effects of decontrol were dramatic.
The shortages ended, black markets disappeared, and Germany’s recovery began. Buying and selling with Deutsche marks replaced barter. Observers remarked that almost overnight the factories began to belch smoke, delivery trucks crowded the streets, and the noise of construction crews clattered throughout the cities.
The remarkable success of the reforms made them irreversible. A few months later the French zone followed suit. The Allied authorities went on to lower tax rates substantially.
Between June and December of 1948, industrial production in the three Western zones increased by an astounding 50%. In May 1949 the three zones were merged to form the Federal Republic of Germany, commonly called West Germany, while East Germany remained under Soviet domination as the German Democratic Republic.
Growth continued under the market-friendly policies of the new West German government. Erhard became the Minister of Economic Affairs, serving under Chancellor Konrad Adenauer from 1949 to 1963. The West German economy not only left East Germany’s in the dust, it outgrew France’s and the United Kingdom’s despite receiving much less Marshall Plan aid. This was the era of the Wirtschaftswunder or “economic miracle.”