The developmental research project described investigated means of improving access to materials in Ontario school resource centers to increase center utilization. The objective of this York Region project was to determine whether, by linking together the power of three computerized systems--MARC (MAchine-Readable Cataloging), COM, (Computer Output Microform), and PRECIS (PREserved Context Index System)--many of the problems that had resulted in under use of school libraries could be solved. This report first places the project in a historical context, describes the purpose of PRECIS in terms of recent needs and opportunities, notes the international range of PRECIS applications, and relates the foregoing to the requirements of present school libraries. Problems associated with the catalogs normally used and how the three computerized systems deal with these problems are then described, as well as project accomplishments and future needs. The final section focuses on the program, begun at Aurora High School in 1972 with a test of PRECIS in the manual mode, that became the starting point for a school library cataloging, information retrieval, elementary/secondary mini-network. Explanations are given for how the various contract objectives were met or missed. Appendices include a glossary, a five-page bibliography, a map of the PRECIS mini-network, a supplement to the AUE Union Catalog, and samples from subject index microfiche and microfiche catalogs for elementary and secondary schools. (LMM)