William M. Brown III John L. Sznopek 1998 <p>Materials extracted from the Earth are necessary to produce our most fundamental needs – food, clothing, and shelter. Materials are needed to maintain and improve our standard of living. Understanding the whole system of materials flow, from source to ultimate disposition, can help us better manage the use of natural resources and protect the environment.</p> application/pdf 10.3133/fs06898 en U.S. Geological Survey Materials Flow and Sustainability reports