In the context of the history of the 20th century, the interwar period was the period between the end of the First World War in November 1918 and the beginning of the Second World War in September 1939.
Despite the relatively short period of time, this period represented an era of significant changes worldwide. Petroleum and associated mechanisation expanded dramatically leading to the Roaring Twenties, a period of economic prosperity and growth for the middle class in North America, Europe and many other parts of the world. Automobiles, electric lighting, radio broadcasts and more became commonplace among populations in the developed world. The indulgences of this era subsequently were followed by the Great Depression, an unprecedented worldwide economic downturn which severely damaged many of the world's largest economies.
Politically, this era coincided with the rise of communism, starting in Russia with the October Revolution, at the end of World War I, and ended with the rise of fascism, particularly in Germany. China was in the midst of long period of instability and civil war between the Kuomintang and the Communist Party of China.