Reproductions of 100 fact sheets received in response to a comprehensive survey of known and suspected Selective Dissemination of Information (SDI) systems are organized into operational, pilot and planned systems. The survey form was designed to give a detailed picture of system design features, organized so that the reader can rapidly locate systems with specific characteristics of interest. These fact sheets are published not only to serve an educational function but to encourage direct informal contact among persons interested in SDI. For this reason, each system description contains the name, address and phone number of the system operator. (NH)