Question: Why do scholars study the causes of the Great Depression?
About the article "Great Depression", section "Causes".

Candidate passages:
Marxists generally argue that the Great Depression was the result of the inherent instability of the capitalist model. 
  Ben S. Bernanke.
"Essays on the Great Depression" (2000)  Bernstein, Michael A.
"The Great Depression: Delayed Recovery and Economic Change in America, 1929–1939" (1989) focus on low-growth and high-growth industries  Bordo, Michael D., Claudia Goldin, and Eugene N. White, eds.
"The Defining Moment: The Great Depression and the American Economy in the Twentieth Century" (1998).
Advanced economic history.
Chandler, Lester.
"America's Greatest Depression" (1970).
economic history overview.
De Long, Bradford.
"Liquidation Cycles and the Great Depression" (1991)  Jensen, Richard J.
"The Causes and Cures of Unemployment in the Great Depression," "Journal of Interdisciplinary History" 19 (1989) 553–83.
online at JSTOR in most academic libraries  McElvaine, Robert S. "The Great Depression" (2nd ed 1993) social history  Mitchell, Broadus.
"Depression Decade: From New Era through New Deal, 1929–1941" (1964), standard economic history overview.
Parker, Randall E. "Reflections on the Great Depression" (2002) interviews with 11 leading economists  Salsman, Richard M. “The Cause and Consequences of the Great Depression” in "The Intellectual Activist", ISSN 0730-2355.
Mr. Salsman argues that the Great Depression was "fundamentally" caused by "statist" government policy.
Singleton, Jeff.
"The American Dole: Unemployment Relief and the Welfare State in the Great Depression" (2000)  Warren, Harris Gaylord.
"Herbert Hoover and the Great Depression" (1959).  
"America's Great Depression" is a 1963 treatise on the 1930s Great Depression and its root causes, written by Austrian School economist and author Murray Rothbard.
The fifth edition was released in 2000. 
Economists such as John Maynard Keynes and Milton Friedman suggested that the do-nothing policy prescription which resulted from the liquidationist theory contributed to deepening the Great Depression.
With the rhetoric of ridicule Keynes tried to discredit the liquidationist view in presenting Hayek, Robbins and Schumpeter asMilton Friedman stated that at the University of Chicago such “dangerous nonsense” was never taught and that he understood why at Harvard —where such nonsense was taught— bright young economists rejected their teachers' macroeconomics, and become Keynesians.
He wrote:Economist Lawrence White, while acknowledging that Hayek and Robbins did not actively oppose the deflationary policy of the early 1930s, nevertheless challenges the argument of Milton Friedman, J. Bradford DeLong et al.
that Hayek was a proponent of liquidationism.
White argues that the business cycle theory of Hayek and Robbins (which later developed into Austrian business cycle theory in its present-day form) was actually not consistent with a monetary policy which permitted a severe contraction of the money supply.
Nevertheless, White says that at the time of the Great Depression Hayek "expressed ambivalence about the shrinking nomimal income and sharp deflation in 1929–32".
In a talk in 1975, Hayek admitted the mistake he made over forty years earlier in not opposing the Central Bank's deflationary policy and stated the reason why he had been ambivalent: "At that time I believed that a process of deflation of some short duration might break the rigidity of wages which I thought was incompatible with a functioning economy."
Three years later, Hayek strongly criticized the Fed's sudden contraction of money early in the Depression and its failure to offer banks liquidity: 
  Harwood, Edward C. (1928), "The Probable Consequences to Our Credit Structure of Continued Gold Export," "The Annalist" (March 23, 1928)  – (1928), "The Underlying Causes of Our Recent Prosperity: Why the End is Near," "The Annalist" (April 13, 1928)  – (1929), "Speculation in Securities vs. Commodity Speculation," "The Annalist" (February 15, 1929)  – (1929), "Deterioration of the American Bank Portfolio--a Ratio Analysis, 1920-28," "The Annalist" (August 2, 1929)