THE PERIOD BETWEEN the Civil War and the First World War was in some ways analogous to the Jacksonian era, but on a more stupendous scale. At the end of the war, in 1865, America turned with a kind of frenzy to economic expansion. Industrialization, given great impetus by the war, now proceeded with breath-taking speed. By 1900, the United States had forged to the top as the world's greatest power. By almost any standard of economic measurement—steel, coal, and oil production, railroad mileage, number of industrial workers, commercial turnover, and aggregate national income—she was ahead of Great Britain and Germany, her principal competitors.
At the same time, the Westward Movement continued and was brought to a close. In these years, the frontier pushed up the westward slopes of the Mississippi Valley, on to the High Plains. The fabulous Cattle Kingdom, comprising parts of Texas, Oklahoma, Colorado, Kansas, Nebraska, Wyoming, and Montana, developed because of the demand for meat to feed America's teeming industrial population. The age of the cowboy came and went. Hard on the heels of the cattle men came farm settlers with plough and barbed wire, tearing up the grass