In 1972, the National Commission on Libraries and Information Science (NCLIS) identified experts to study and report on the information needs of selected groups within the United States population: six occupational and professional groups, various age groups, women, the handicapped, the isolated, and ethnic groups--mainly the Mexican American community. The groups were analyzed in terms of characteristics, rationale for service, needs for library and information services, inadequacies in existing services, and strategies for change. The reports of the 16 experts were presented at the NCLIS User Conference at the University of Denver, Colorado, in May, 1973. The second day of the conference was devoted to three work groups who considered various aspects of the information needs problem. A needs-description matrix was formulated to provide a common format, through which the needs of various client groups could be compared. This report presents the conference papers, the proceedings of the working groups, an analysis of the needs-matrix, and the conference summary and implications report. (SL)