An inscription on the wall of the Chinatown History Project in New York City says: “It is true that history cannot satisfy our appetite when we are hungry, nor keep us warm when the cold wind blows. But it is also true that if younger generations do not understand the hardships and triumphs of their elders, then we will be a people without a past. As such, we will be like water without a source, a tree without roots.”

The United States is the world's greatest economic power in terms of gross national product (GNP) and is among the greatest powers in terms of GNP per capita. The nation's wealth is partly a reflection of its valuable natural resources. With only 5 % of the world's population, the United States produces nearly one-fifth of the world's output of coal, copper, and crude petroleum. The agricultural area produces nearly one-half of the world's corn ;nearly one-fifth of its beef, pork, mutton, and lamb; and more than one-tenth of its wheat. The United States owes its economic position more to its highly developed industry, than to its natural resources or agricultural output.

contempt its relative self-sufficiency, the United States is the most valuable single factor in world trade by virtue of the sheer size of its economy. Its exports represent more than 10 % of the world total. The United States impinges on the economy of the rest of the world not only as a trading power but also as a source of investment capital. Direct investment abroad by U.S. firms is a dominant factor in the economies of Canada and many Latin-American countries and is also valuable in Europe and in Asia.