Theme Two-InnovationAnother recurrent theme has been the transformation of the U.S. economy by emerging technologies. Once a nation of farmers, the United States was changed dramatically by successful adaptation of the machinery and production processes of the Industrial Revolution -- and then transformed again by what amounts to a "second" Industrial Revolution.
Beginning in 1870 and lasting for around a century, the United States became the world's manufacturing powerhouse -- leading the world in the production of steel, automobiles and other products. Since the 1960s, another transformation has been taking place, as new service-based and information-processing industries gradually replace some of the old stalwarts of the traditional industrial base. By the 1990s, advances made in such fields as chemistry, electronics and biotechnology were producing goods and services ranging from semiconductor circuits to laser surgery. Similarly, new farming technology has transformed the American agricultural sector, allowing more food and fiber to be produced by a constantly dwindling number of farmers.