A set of 47 one- and two-page discussions of pressing environmental problems, ranging from oil slicks to algae overgrowth, from evaporative loss of the world's helium supply to whether nonuse of DDT may be more dangerous than use, from Arctic sewage and nuclear wastes to giant starfish eating up the coral reefs, and what may happen if all rats are destroyed. Each includes a statement of the problem, quotes from news items and semitechnical journals, and suggestions for RAND research. Finding uses for the unwanted--sewage, junk, garbage, radioactive materials, thermal pollution, algae--is a recurrent theme, as is developing ability to monitor pollution and assess the costs to the polluters. Biological solutions are preferred, and so is using one problem to solve another, such as making underwater reefs of junked cars, and perhaps collocating gas reliquefying plants (which lower water temperatures) with power plants (which raise them). 72 pp.