The United States of America is the world's third-largest country in terms of both size and population. It shares borders with the world's two largest oceans-the Atlantic, to the east, and the Pacific, to the west-and with the nations of Canada, to the north, and Mexico, to the south. The United States is well known for its environmental and cultural diversity. All of the world's major climates-from Arctic to subtropical, and from desert to rain forest-can be found within its borders. In addition, its population is one of the most diverse in the world. Throughout its history, the United States has been defined by sustained periods of immigration that have brought varied groups of immigrants: first from western Europe; then from southern and eastern Europe; and, most recently, from Asia and Latin America. The United States also is defined by its abundant natural resources and voluminous economy. The country has vast stores of coal and oil and is the world's leading producer of electrical and nuclear energy.

In addition, it is responsible for 60 percent of the world's agricultural output. Despite being home to less than 5 percent of the world's population, the United States is the world's largest economy, accounting for 20 percent of the global gross domestic product and approximately 10 percent of the world's exports. Book jacket.