Book excerpt: In this volume, the author develops a new approach for the analysis of differing types of informations systems, called the Value-Added Model. This approach is based on the anlaysis of information-use environments and on the system responses to the needs of those environments. The model is applied to a variety of information systems. Document-based systems, academic, public, and special libraries, abstracting and indexing services, and book publishing are among those analyzed. Within decision systems, the author looks at management information systems and decision support systems within the value-added framework.