Computers show every sign of becoming deeply seated in the process of doing science by influencing the design and scope of experiments, data collection and data analysis and by facilitating the study, preparation and publication of scientific results. Of increasing importance to the life scientist is the analysis and quantification of images, particularly as an aid to the understanding of the relationship between structure and function. The nature of the routine acquisition and transmission of images taxes to the limit every aspect of current computer technology. These challenges apply to processor design, to mass storage of data and to the focus of this application, network communication. One of the most important trends in the evolution of scientific computing has been toward decentralized systems, bound together in a Local Area Network (LAN). For scientists who have problems that are intractable in a time-shared computing environment, a collection of specialized processors connected by means of a LAN is becoming the de facto method for carrying out their work. At Washington University, there are already several LANs that link the computers of a few biomedical investigators. This grant will be used to obtain the instrumentation necessary for the reliable operation and smooth growth of a network for biomedical research, to purchase the equipment for a high-speed link between LANs at the University's hilltop campus and the medical campus and to provide network access devices to a broad community of biomedical investigators at Washington University.