The Wall Street Crash of 1929, also known as Black Tuesday or the Stock Market Crash of 1929, began in late October 1929 and was the most devastating stock market crash in the history of the United States, when taking into consideration the full extent and duration of its fallout. The crash signaled the beginning of the 10-year Great Depression that affected all Western industrialized countries.
The New Deal was a series of domestic programs enacted in the United States between 1933 and 1938.
The programs were in response to the Great Depression, and focused on what historians call the "3 Rs": Relief, Recovery, and Reform.
That is Relief for the unemployed and poor; Recovery of the economy to normal levels; and Reform of the financial system to prevent a repeat depression.
Keynesian economics is the view that in the short run, especially during recessions, economic output is strongly influenced by demand.