The United States has made remarkable progress over the past 30 years in reducing pollution and protecting the environment within its borders. Statistics help tell the story. During this time, the U.S. economy grew by 187 percent, population grew by 39 percent, and energy consumption increased by 47 percent, yet air pollution decreased by 48 percent. In 2002, 94 percent of Americans were served by community water systems that met all health-based standards, up from 79 percent of the population in 1993.

The United States has taken a leadership role as a global environmental steward in developing a better understanding of environmental options and in shaping a sustainable approach to development. Achieving greater sustainability is a key objective in the provision and management of energy. New technologies offer the possibility of renewable energy sources that do not contaminate the air and the water, or release greenhouse gases and destroy Earth's protective ozone layer. New technologies also promise ways in which we may more efficiently utilize traditional energy resources.

Such technological innovation and development demand participation of the broad reach of society. In the United States, business, industry, and science are increasingly playing critical roles in shaping national strategies for greater energy conservation and wiser resource management and disposal.

Environmental stewardship is critical to the promise of a better life for people around the world, and authors on these pages emphasize that theme as they discuss climate change, alternative energy innovations, air quality, forest and freshwater management, and waste recycling. Included are an extensive bibliography and a collection of Web resources. Two photo stories document environmental progress over the past three decades and the development of "green" technologies, which are preparing our world for a better tomorrow.

Our distinguished contributors include Under Secretary of State Paula Dobriansky, White House Science Advisor John Marburger, Environmental Protection Agency Assistant Administrator Jeffrey Holmstead, and many dedicated scientists, activists, and citizens committed to protecting the planet we all share and on whose resources we all depend.