Editors' Summary: Much attention has been focused on the role of statutes in environmental enforcement. This focus is understandable, given the huge arsenal of environmental statutes that have been enacted. But the courts have not forgotten the common law, and as this article points out, neither should litigants. Approaching the subject from the perspective of the state enforcement official, the article discusses the applicability of the common law concept of public nuisance to modern-day environmental problems, particularly those caused by hazardous waste and toxic substances. The author argues that in many situations, the public nuisance doctrine provides enforcement officials with powerful flexibility not otherwise available. In this first of three parts, the author sets the stage for an appropriate understanding of the modern potential of public nuisance by discussing the history of public nuisance, analyzing the doctrine's original purposes, and examining how the concept has changed over the years. A second article will look at remedies available to the state litigator and possible defenses that may be raised.