This monograph studies the relationships between the technical, economic, and financial aspects of petroleum, natural gas, coal, and uranium supply from primary sources. The analysis presented applies to any country with energy resources, but is addressed particularly to energy planners in the developing countries. Management of an energy program requires expertise and confidence in assessing the economic feasibility of development of internal as well as external energy sources. Such assessment is interdisciplinary in nature, requiring expertise in geology, geophysics, exploration management, resource engineering, and marketing.