Editors' Summary: Exactly 20 years ago this month, in February 1969, Senator Henry Jackson (D-Wash.) and Rep. John Dingell (D-Mich.) introduced draft legislation that led the way to the ultimate enactment of the National Environmental Policy Act. A product of the growing environmental consciousness of American society during the 1960s, NEPA was Congress' first modern environmental law, and it set the tone for the complex superstrucure of federal environmental law that was to follow. Even now, as NEPA approaches age 20, it stands out as probably the single most widely applicable federal environmental statute, and its visionary approach to environmental issues makes it as adaptable to the problems of 1989 as it was to the problems of 1969. In this Article the author, the General Counsel of the Council on Environmental Quality, outlines NEPA's purposes, scope, and implementation procedures. She describes current issues in NEPA practice and policy, and observes that NEPA has continuing vitality in the context of a new generation of environmental concerns that could only have been guessed at by its original supporters.