© 2003 David Koeller. All rights reserved. The Great Depression Begins. 1929. The leading theory regarding the cause of The Great Depression holds that it resulted from the stock market crash in 1929. © 2003 David Koeller. All rights reserved. The Great Depression Begins. 1929. The leading theory regarding the cause of The Great Depression holds that it resulted from the stock market crash in 1929. Interpretations on the causes for the great depression of the 1930's. The Great Depression was the worst economic slump ever in U.S. history, and one which spread to Robert S. McElvaine, The Great Depression: America 1929-1941 (New York: Times The Great Economic Depression of 1929. A crisis of historical magnitude. On Wednesday October 23, there was an unexpected fall in stock prices. For the American agriculture, the Great Depression climbed on top of a five year old ongoing crisis Interpretations on the causes for the great depression of the 1930's. The Great Depression was the worst economic slump ever in U.S. history, and one which spread to Robert S. McElvaine, The Great Depression: America 1929-1941 (New York: Times