Don Watkins has an excellent article on The Great Depression and the Role of Government Intervention over at the Voices for Reason blog. Here is a brief summary:
The Myth: An unregulated free market and unrestricted Wall Street greed caused the Great Depression and only the interventionist policies of Franklin D. Roosevelt got us out.
The Reality: The Great Depression was caused by government intervention, above all a financial system controlled by America’s central bank, the Federal Reserve — and the interventionist policies of Hoover and FDR only made things worse.