Despite the varied theories espoused by many establishment economists, it was none other than the Federal Reserve that caused the Great Depression and the horrific suffering, deprivation and dislocation America and the world experienced in its wake. At least, that's the clearly stated view of current Fed Chairman Ben Bernanke.
The worldwide economic downturn called the Great Depression, which persisted from 1929 until about 1939, was the longest and worst depression ever experienced by the industrialized Western world. While originating in the U.S., it ended up causing drastic declines in output, severe unemployment, and acute deflation in virtually every country on earth. According to the Encyclopedia Britannica, "the Great Depression ranks second only to the Civil War as the gravest crisis in American history."
What exactly caused this economic tsunami that devastated the U.S. and much of the world?
In "A Monetary History of the United States," Nobel Prize-winning economist Milton Friedman along with coauthor Anna J. Schwartz lay the mega-catastrophe of the Great Depression squarely at the feet of the Federal Reserve.

At a Nov. 8, 2002, conference to honor Friedman's 90th birthday, Bernanke, then a Federal Reserve governor, gave a speech at Friedman's old home base, the University of Chicago. Here's a bit of what Bernanke, the man who now runs the Fed – and thus, one of the most powerful people in the world – had to say that day:

I can think of no greater honor than being invited to speak on the occasion of Milton Friedman's ninetieth birthday. Among economic scholars, Friedman has no peer. … Today I'd like to honor Milton Friedman by talking about one of his greatest contributions to economics, made in close collaboration with his distinguished coauthor, Anna J. Schwartz. This achievement is nothing less than to provide what has become the leading and most persuasive explanation of the worst economic disaster in American history, the onset of the Great Depression – or, as Friedman and Schwartz dubbed it, the Great Contraction of 1929-33.
… As everyone here knows, in their "Monetary History" Friedman and Schwartz made the case that the economic collapse of 1929-33 was the product of the nation's monetary mechanism gone wrong. Contradicting the received wisdom at the time that they wrote, which held that money was a passive player in the events of the 1930s, Friedman and Schwartz argued that "the contraction is in fact a tragic testimonial to the importance of monetary forces."

After citing how Friedman and Schwartz documented the Fed's continual contraction of the money supply during the Depression and its aftermath – and the subsequent abandonment of the gold standard by many nations in order to stop the devastating monetary contraction – Bernanke adds:

… Before the creation of the Federal Reserve, Friedman and Schwartz noted, bank panics were typically handled by banks themselves – for example, through urban consortiums of private banks called clearinghouses. If a run on one or more banks in a city began, the clearinghouse might declare a suspension of payments, meaning that, temporarily, deposits would not be convertible into cash. Larger, stronger banks would then take the lead, first, in determining that the banks under attack were in fact fundamentally solvent, and second, in lending cash to those banks that needed to meet withdrawals. Though not an entirely satisfactory solution – the suspension of payments for several weeks was a significant hardship for the public – the system of suspension of payments usually prevented local banking panics from spreading or persisting. Large, solvent banks had an incentive to participate in curing panics because they knew that an unchecked panic might ultimately threaten their own deposits. It was in large part to improve the management of banking panics that the Federal Reserve was created in 1913. However, as Friedman and Schwartz discuss in some detail, in the early 1930s the Federal Reserve did not serve that function. The problem within the Fed was largely doctrinal: Fed officials appeared to subscribe to Treasury Secretary Andrew Mellon's infamous 'liquidationist' thesis, that weeding out "weak" banks was a harsh but necessary prerequisite to the recovery of the banking system. Moreover, most of the failing banks were small banks (as opposed to what we would now call money-center banks) and not members of the Federal Reserve System. Thus the Fed saw no particular need to try to stem the panics. At the same time, the large banks – which would have intervened before the founding of the Fed – felt that protecting their smaller brethren was no longer their responsibility. Indeed, since the large banks felt confident that the Fed would protect them if necessary, the weeding out of small competitors was a positive good, from their point of view.
In short, according to Friedman and Schwartz, because of institutional changes and misguided doctrines, the banking panics of the Great Contraction were much more severe and widespread than would have normally occurred during a downturn. …
Let me end my talk by abusing slightly my status as an official representative of the Federal Reserve. I would like to say to Milton and Anna: Regarding the Great Depression. You're right, we did it. We're very sorry. But thanks to you, we won't do it again.
Best wishes for your next ninety years.

Today, the entire Western financial world holds its breath every time the Fed chairman speaks, so influential are the central bank's decisions on markets, interest rates and the economy in general. Yet the Fed, supposedly created to smooth out business cycles and prevent disruptive economic downswings like the Great Depression, has actually done the opposite.