A statement from President Nixon, and from Senator Muskie.--The limited war on water pollution, by G. Bylinsky.--Industry starts the big cleanup, by J. Davenport.--What business thinks about its environment, by R. S. Diamond.--The economics of environmental quality, by S. Rose.--Cars and cities on a collision course, by A. T. Demaree.--How Baltimore tamed the highway monster, by J. Gooding.--Some burning questions about combustion, by T. Alexander.--It's time to turn down all that noise, by J. M. Mecklin.--Downtown is looking up, by W. McQuade.--Conservationists at the barricades, by J. Main.--Victory on San Francisco Bay, by J. Gooding.--Our new awareness of the great web, by W. Bowen.--How to think about the environment, by M. Ways.