One of the most widely discussed books on the environmental dilemma is “The Closing Circle” by Barry Commoner, director of the Center for Biology and Natural Systems at Washington University, St. Louis. Shortly after its publication (Knopf, 1971), a critique of the book was issued by Paul R. Ehrlich, professor of biological sciences at Stanford University, and John P. Holdren, a physicist at the Environmental Quality Laboratory, California Institute of Technology. Professor Ehrlich, also author of a widely discussed book, “The Population Bomb” (Ballantine, 1968, 1971), and Dr. Holdren state in part that “in fixing the blame for environmental deterioration on faulty technology alone, Commoner's position is uncomplicated, socially comfortable and, hence, seductive. But there is little point in deluding the public on these matters; the truth is that we must grapple simultaneously with overpopulation, excessive affluence and faulty technology.” The Bulletin herewith presents the Ehrlich-Holdren critique and Commoner's response.