Existing private, public, and semipublic organizations with an interest in the Potomac or in the type of problems it presents have joined in the present effort by sponsoring public meetings and publishing discussions or otherwise doing their part to help. Among them may be mentioned INCOPOT, the Conservation Foundation, the Metropolitan Washington Council of Government, Resources for the Future, Inc., the League of Women Voters, the Potomac Basin Center, the National Parks Association, and a number of local planning or action bodies. Through these meetings and other media, public comment on the Federal Task Force's work has been voluminous and often helpful, particularly since the publication of its _Interim Report_ in January of 1966, which made certain proposals for immediate action to begin providing for short-term metropolitan water needs, to protect specific scenic treasures, and to get moving on the long task of cleaning up the river. With so many viewpoints somehow included in the planning process, opinions have often diverged as to how much of what ought to be done about the Potomac, and how soon, and in what order. Well they may diverge. In a time of economic expansion and population growth unparalleled in human history, predictions about the economy and the population of the distant future--necessary to full planning--verge perilously near to crystal gazing even when the best available yardsticks are applied. And this is only one uncertainty. Among the others which will be examined later in this report are the prospect of drastic technological change that may soon offer cheaper, more effective, and less disruptive ways of dealing with environmental problems including water; the doubtfulness of sufficient public money for large conservation projects in a time of international tensions and urban crisis; and the solid American political complexity of the boundary-laced Potomac Basin, which bristles with various forms of veto power and a multiplicity of assorted regional, professional, and philosophical viewpoints. Such complexities and uncertainties have a powerful reality and relevance for planners. They impose a need for breadth of view, for leaving many future options open, and by the same token they present a danger of piecemeal action, excessive compromise and indecisiveness.