In this article, originally published in Scientific American, Amory Lovins dispels the myth that protecting the earth’s climate will force a trade-off between the environment and the economy. Instead, he shows that efficiency is profitable. Focusing on energy efficiency improves the bottom line and yields many valuable side benefits. Whole-systems engineering can be applied to vast numbers of systems to increase efficiency, thereby increasing profits. Technological advancements in the transportation industry (such as ultralight cars), and renewable energy improvements (such as wind, solar, and other renewable resources) are evidence that smarter design and integration can decrease our dependence on fossil fuels and are financially advantageous. Additionally, Lovins argues that the globalized economy is stimulating many new energy investments. If government can remove institutional barriers and harness free enterprise, the markets will naturally favor choices that generate wealth, protect the climate and build security by replacing fossil fuels with cheaper alternatives. The complete bibliography of this article is also available (RMI document ID C05-05a).