This paper begins with a discussion of the decision-making process. The application of operations research technologies to managerial decision-making is noted, and the development of management information systems in organizations and some limitations of these systems are discussed. An overview of the Human Information Processing System (HIPS) model and its three subsystems--external memory, short-term memory, and long-term memory--is then presented, and the concepts of problem space and bounded rationality are introduced. A description of the architecture of an expert system covers its two basic components: (1) the knowledge base and working memory; and (2) the inference system and control subsystem. Several applications of expert systems by library managers and operational groups are identified, and a prediction that expert systems will have a bright future in libraries and more user-oriented applications concludes the paper. (15 references) (MES)