Don't get me wrong. I am not saying that central banks can completely prevent the boom and bust cycles that have plagued market economies from time immemorial.
There was very little that the Fed could do to prevent the 1990 recession caused by the real estate bust and soaring oil prices triggered by Saddam Hussein's invasion of Kuwait. Nor could the central bank prevent the 2000 recession caused by the popping of the technology bubble and 9/11. But central banks have reduced the severity of recessions by preventing a financial panic from developing into a full-blown economic collapse.
~ Jeremy Siegel, "Don't Blame the Central Banks -- Thank Them," Yahoo Finance, September 27, 2007