American society, with a standard of living unprecedented in human history, can attribute a large measure of its success to increasingly sophisticated uses of energy. But that condition has come at a cost—to irreplaceable resources, to the environment, and to our national independence. The goal of What You Need to Know About Energy is to present an accurate picture of America's current and projected energy needs and to describe options that are likely to play a significant role in our energy future. Written for a general audience, the booklet begins with a description of the status of energy in 21st-century America, including an account of our main sources of energy and a survey of the nation's energy demand versus the world's available supply. It then looks ahead to the quest for greater energy efficiency and to a portfolio of emerging technologies.