In a prior post ( here ), I took a Systems Theory perspective to defining the Great Depression . From that perspective (Path A here ), there really wasn't a Great Depression, as such, but rather an Economic Bubble that started with World War I ( WWI ) and ended when the Bubble was popped by the Stock Market Crash of 1929 . From Another perspective ( Path B here ) something bad did (or did not) happen that created a massive economic collapse. Path B is the conventional explanation which led to a vast literature (see the Notes below) driven by Monetary Theory , Keynesian Theory and other perspectives ( Systems Theory is not one of the conventional perspectives ) . In this post, I look at Path B more carefully. I eliminate the two dominant historical controllers in the US_E20 Model ( US2 and US3 ) to show that, without them, there was no Crash. The biggest shock to US1 is from US3 which invo...