Contents

31 August 1984
Vol 225, Issue 4665

About The Cover

Dirt to dirt and rust to rust. Our national economy is based on an investment of high-quality energy to upgrade natural resources into economically useful forms and to maintain finished products against natural entropic decay. There are strong statistical relations between energy use and important macroeconomic indicators for the United States—such as gross national product, labor productivity, and inflation—over the past 60 to 100 years. See page 890. [David Skole, Complex Systems Research Center, University of New Hampshire, Durham 03824]