Continuing with more excellent excerpts from Applied Economics by Thomas Sowell.

This one is on Government intervention in depressions and comes from the chapter titled Politics versus Economics:

Prior to the Great Depression of the 1930s, there was no tradition of federal government intervention to get the United States out of depressions. Roosevelt's predecessor, President Herbert Hoover, was the first President to take on that responsibility, and many of his interventions were later simply carrier much further by FDR, despite a political myth that persisted for years that Hoover was a "do nothing" President. In much later years, even prominent former advisers of the Roosevelt administration admitted that FDR's New Deal was a further extension of what Hoover had been doing. Herbert Hoover was in fact the first President to decide to "do something" on a national scale to try to extricate the country from a depression, though there is no evidence that what he did made things any better and there is considerable reason to believe that they made things worse.

Earlier in the 1920s, a sharp decline in the economy had been largely ignored by President Calvin Coolidge-- and the economy pulled out of its decline in relatively short time, as it had pulled out of other such declines in the past. There was nothing inevitable about a stock market crash leading to a decade-long depression. Moreover, as Professor Peter Temin or M.I.T. has noted, the 1929 stock market crash was not unique:

The stock market has gone up and down many times since then without producing a similar movement in income. The most obvious parallel was in the fall of 1987. The isomorphism was uncanny. The stock market fell almost exactly the same amount on almost exactly the same dates.

Another study referred to the October 19, 19878 decline as "by far the worst precentage decline day in the stock market's history." In 1987, however, President Ronald Reagan did not react as Presidents Hoover and Roosevelt had in the wake of the 1929 stock market crash. Instead, like Coolidge before him (whom he admired,) Reagan let the economy recover on its own. Far from leading to a Great Depression, the recovery began one of the longest periods of sustained high employment, low inflation, and general prosperity in American history. At the time, however, President Reagan was sharply criticized in the Washington Post for a "do-nothing, let-the-problems-accumulate, Calvin Coolidge act of the 1980s" and was denounced in the New York Times for having "squandered the opportunity" to take action.