Late 1800s: Booming industrialization demands a large, cheap workforce. The numbers of women and children laborers increases dramatically, but living conditions for poor families often remain squalid. Demands for better pay and working conditions lead to strikes and violence. Between 1881 and 1905 there are approximately 37,000 strikes across the country.

Today: Labor unions and laws protect worker interests. Children are prohibited from working until a certain age, and all workplaces have regulations about safety, hours, and wages.

Late 1800s: Monopolies and trusts control most of the industrial power in the country, and enormous wealth is concentrated in the hands of a few such as Rockefeller (oil), Vanderbilt (railroads), Morgan (banks), Carnegie (steel), and Duke (tobacco).

Today: Antitrust laws prevent the use of unfair competition by conglomerates to drive small businesses out of the market. The most notable recent antitrust case involved Microsoft.

Late 1800s: Many new...