The realization that the facilities available for the retrieval of scientific and technical information were being underutilized resulted in a project undertaken by the Drexel University School of Library and Information Science to develop a computer intermediary capable of assisting users of scientific and technical information in the performance of online bibliographic searches. Individualized Instruction for Data Access (IIDA), the computer system developed during the project, operates in an instructional and an assistance mode, and can be used to train users to perform online searches or to aid users in search performance. The system employs a set of diagnostics which alert users to the strategic and syntactic errors they make during the search process. When IIDA was operational, a number of evaluations of the system were made, using first undergraduate computer science majors and experienced online searchers, then library science faculty and graduate students and undergraduate engineering students, and finally engineers at the Exxon Research facility in Florham Park, New Jersey. The evaluation studies indicated that individuals who had never done online searching were able, using IIDA, to do searches which produced satisfactory results. Detailed accounts of the design of the system, system operations, and the methodology of the evaluation studies are given, and the project bibliography is included. (JL)