The method by which the Federal Reserve caused (and then sustained) the Great Depression was to first massively expand the money supply (causing the roaring 20's) and then massively remove money from circulation. This brought the worlds greatest nation, with more fully functioning factories, more productivity, more natural resources, more food production, and more energy than the rest of the world combined at the time to its knees. We lacked nothing but money.
Virtually the exact same thing had happened only a few decades earlier when silver was demonetized and the bi-metal money standard (of silver and gold) was terminated and replaced with a purely gold standard. Since much of the wealth of the USA at the time was in silver, and there is a fixed amount of gold, the demonetization of silver contracted the money supply greatly, and people starved. The government at work again. One man who fought against the passage of the "gold only" standard was William Jennings Bryan, who's "Cross of Gold" speech on the Senate floor in 1896 is to this day considered the most famous political speech ever made. It ends with these words: "You shall not press down upon the brow of labor this crown of thorns, you shall not crucify mankind upon a cross of gold."
Soon afterwards gold and the gold standard (through no fault of gold on its own, since gold was not re-valued to take up for the lack of silver) was declared a total failure and the Federal Reserve was born to cure the ills that "gold" had brought upon us. All because much to perhaps most of the wealth of the nation was demonetized, and this effectively contracted the money supply big time.