The document summarizes key events and developments in the United States between 1920-1939, including:
1) After World War I, Americans embraced isolationism and elected Republican presidents Warren G. Harding and Calvin Coolidge who promised a "return to normalcy." However, both administrations were plagued by scandals.
2) The 1920s saw widespread economic prosperity and consumerism fueled by new technologies, easy credit, and mass marketing through growing advertising industries.
3) The stock market crash of 1929 marked the beginning of the Great Depression, and Republican Herbert Hoover lost the 1932 election to Democrat Franklin D. Roosevelt, who implemented his New Deal programs.