Microorganisms are unquestionably important in chemical pollution and pollution abatement. They are environmental decontaminating agents par excellence, ridding waters and soils of many natural and synthetic compounds which are not desired at that time or place or concentration. They sometimes are significant, too, because they may synthesize hazardous substances from reasonably innocuous precursors. Their occasional inadequacies must be cited as well, failings that become obvious when an organic molecule endures for many years. Conversely, because of the essentiality of many processes catalyzed by algae, bacteria, fungi, and protozoa, a chemically-induced change in one or more of those functions important in nature may have serious local, regional, or possibly global consequences. Activity in pollution microbiology, and in the basic aspects of microbial ecology without which information little meaningful data in the applied disciplines can be obtained, is increasing by leaps and bounds. Microbial ecology, both theoretical and mission oriented, is climbing to the forefront of microbiology, ecology, and other environmental sciences. Time will tell whether it lives up to its promises. 27 references.