IN THIS ISSUE: Using Waste Materials: A Challenge for Engineers /2 (An industrialist and chemical engineer explores the economic as well as social reasons for in-plant utilization of waste materials rather than disposal. Herbert D. Doan, a member of the board of directors and former president of the Dow Chemical Company, is a Cornell graduate and serves on the Engineering College Council.) ... Food From Organic Refuse /8 (The production of microbial protein by growing it on organic wastes and the concept of the "urban farm" are among subjects discussed by Victor H. Edwards, assistant professor of chemical engineering at Cornell, in an interview with Quarterly editor Gladys J. McConkey.) ... Recover, Reuse, Recycle: New Approaches to the Solid Waste Problem /18 (Charles D. Gates, professor and acting chairman of Cornell's Department of Environmental Engineering, discusses the technological and economic feasibility of solid waste management systems and what needs to be done to encourage resource recovery.) ... Engineering Landfill for Reuse of Sites /24 (Not only solid wastes themselves but the land on which they are buried represent resources that can be recovered and reused. The reclamation of landfill sites is discussed by Dwight A. Sangrey, an associate professor at the Cornell College of Engineering and a specialist in soils and geotechnical engineering.) ... Commentary /29 (The nation's critical energy requirements as they impinge on the need for preservation of the environment are discussed by Peter L. Auer, Cornell professor of aerospace engineering and director of the Laboratory of Plasma Studies. His remarks are excerpted from his summary address at the Cornell Workshop on Energy and the Environment, at which leading United States authorities considered the issues and formulated proposals for future energy supply and management.) ... Faculty Publications /37