During the second half of the nineteenth century, the United States emerged as a major industrial nation. Industrialization involves a population movement from rural to urban areas and a shift from producing goods at home or in small shops to manufacturing them in factories. By the 1890s, industries were enjoying large profits and employing millions of people. There were drawbacks as well. Cities grew crowded and dirty, and there was an ever widening gap between wealthy industrialists and workers. Large businesses began overwhelming smaller ones.

Some businesses that created similar products or provided similar services combined to form trusts—a business combination formed to reduce competition and control prices. Trusts dominated such commodities as oil and coal, beef and sugar, and railroads. By 1900, there were over two hundred trusts operating in the United States. Since a trust...