Petroleum has remained an important aspect of our lives and will do so for the next four or five decades. The fuels that are derived from petroleum supply more than half of the world total supply of energy. Gasoline, kerosene, and diesel oil provide fuel for automobiles, tractors, trucks, aircraft, and ships. Fuel oil and natural gas are used to heat homes and commercial buildings, as well as to generate electricity. Petroleum products are the basic materials used for the manufacture of synthetic fibers for clothing and in plastics, paints, fertilizers, insecticides, soaps, and synthetic rubber. The uses of petroleum as a source of raw material in manufacturing are central to the functioning of modern industry. Petroleum refining is now in a significant transition period as the industry has moved into the 21st century and the demand for petroleum products has shown a sharp growth in recent years, especially with the recent entry of China into the automobile market. This means that the demand transportation fuels will, without doubt, show a steady growth in the next decade, contributing to petroleum product demand patterns that can only be fulfilled by the inclusion of heavier feedstocks into refinery operations.