Information is a staple of modern society upon which nearly every human being depends. Yet there is a mismatch between the information needs and the information that is available. To assess information needs, a conceptual framework must be built. Information is defined as a symbol or set of symbols which has the potential for meaning. Finding a useful definition of information needs has been elusive, and the continued study of information needs in various contexts, together with the process by which information is communicated, is important. While there are no uniformly acceptable procedures for determining information needs, the methodologies of the social have direct applications. Many studies have been done concerning information needs. There may be conveniently classified in one of the following categories: science, social science, the professions, or the general public. The emphasis of past studies clusters into four groupings: (1) the behavior of the user, (2) the nature, amount and source of information being sought, (3) the quality of the information, and (4) the timeliness of the information. Given the findings of past needs studies, 12 guidelines for the design of information systems are presented. (DC)