A wide range of exciting discoveries, developments, and advancements whose seeds had been planted in earlier years blossomed during the 1920s. What had once been the dreams and visions of farsighted scientists, researchers, and inventors became, to varying degrees, normal parts of many people's daily lives.

Perhaps the leading example is the automobile. This vehicle was already in existence at the beginning of the twentieth century, but it was not a common sight on the roads of the nation until the 1920s, when car ownership rates skyrocketed. It was during this decade that Henry Ford (1863–1947) and other automobile manufacturers made cars that almost anybody could afford to buy. In 1919 there had been 6.9 million passenger cars in the United States, but by 1929 there were 23 million.

A similar story is told in the development of the airplane. The first manned flight had taken place...