The "National Inventory of Library Needs" being conducted by the National Commission on Libraries and Information Science covers public libraries, school library/media centers, and academic libraries. The resource categories being used for the Inventory are staffing, collections, acquisitions, space, and operating expenditures. For example, the need indicator identified for public library staffing is one full-time equivalent professional per 6,000 persons in the population served. The indicators represent generalized versions of detailed library standards typical of many nations and common in states of the United States. Since the indicators are minimums, a library barely meeting all of them would not necessarily be able to provide fully adequate service. The assessment of gaps nationally in the numbers of staff, in the sizes of collections and rates of acquisition of print and audiovisual materials, and in library space should highlight priority needs. The Inventory is a start toward a system of quantitative information for planning information services. (Author/PF)