Short answers, pulled from the story.
The post-World War II economic expansion was a broad period of worldwide economic growth that began with the aftermath of World War II and ended with the 1973-1975 recession. It is also known as the postwar economic boom or the Golden Age of Capitalism, and it featured unusually high, sustained growth alongside full employment in countries including the United States, the Soviet Union, Australia, and Western European and East Asian nations.
Economic historians generally place the start around 1950, though Robert Skidelsky names 1951 as the most recognized start date, and the generally recognized end date is 1973. In France the period, called the Trente Glorieuses, is considered to run across the thirty years from 1945 to 1975.
Causes include continued high productivity growth, the adoption of Keynesian economic policies, heavy infrastructure and military spending, financial repression, wealth redistribution through progressive taxation, and low oil prices. International cooperation also mattered, with the Marshall Plan pumping over $12 billion into Western Europe in 1948 and institutions like the United Nations and the Bretton Woods monetary system promoting stability.
OECD members saw real GDP growth averaging over 4% a year in the 1950s and nearly 5% a year in the 1960s. By Angus Maddison's estimates for 1950 to 1973, Japan grew fastest at 9.29%, followed by Spain at 6.60% and Germany at 5.68%.
The boom ended with a cluster of events in the early 1970s, including the collapse of the Bretton Woods monetary system in 1971, President Richard Nixon closing the gold window, the 1973 oil crisis, the 1973-74 stock market crash, and the 1973-75 recession. The sharp rise in oil prices hastened the transition to a post-industrial economy.
In the United States, Gross Domestic Product rose from $228 billion in 1945 to just under $1.7 trillion in 1975, when the US economy made up about 35% of world industrial output. The middle class swelled and migrated toward the suburbs, $200 billion in war bonds matured, and the G.I. Bill financed a well-educated workforce.