Before the current uses of petroleum were discovered, its main applications were waterproofing and light emission. In the mid-1800s, it was found that a liquid fuel called "kerosene" could be isolated from crude oil. Kerosene was important because it was used a great deal for lighting purposes during the rest of the 19th century.

During the industrial revolution of the late 1890s, new energy sources were required to fuel the innovations constantly being discovered. Thus, people began to experiment with crude oil's other properties. Distilled petroleum began to overtake coal as the primary heating fuel. Furthermore "gasoline," a fuel that could be distilled from crude oil, took on central importance in industrialized societies because of the inventions of the automobile and the internal combustion engine.

Furthermore, the development of electricity around the turn of the century increased demand for fuels that could be burned to power generators, thus increasing demand for petroleum. Petroleum can also be directly combusted to heat houses and other buildings. Unfortunately, because crude oil contains a number of impurities such as sulfur and nitrogen, its combustion can contribute to pollution and the greenhouse effect.

At first, it was believed that the United States controlled the greatest portion of the world's oil supply. Indeed, America did contain relatively extensive oil fields in both Texas, and, as it was later discovered, in Alaska. The British in turn began to exploit oil reserves the world over, especially in the Middle East. Currently, most of the oil used by the industrialized nations is imported from the Middle Eastern countries.

It has been estimated that there are enough crude oil reserves to last the world about another 60 years. More than half of that amount is located in the Middle East in such "oil-rich" countries as Saudi Arabia, Kuwait, Iran, and Iraq. Because so much petroleum is concentrated in that area of the world, imagine how disastrous it would be if the flow of crude oil from that small collection of countries were to suddenly somehow be cut off. Just such a situation did arise during what has been termed the "Mideast Oil Crisis" of the 1970s.