The Minnesota Computer Aided Library System (MCALS) provides a basis of unification for library service program development in Minnesota for eventual linkage to the national information network. A prototype plan for communications functions is illustrated. A cost/benefits analysis was made to show the cost/effectiveness potential for MCALS. System costs, system benefits, personnel allocation, building space requirements, and transfers of library materials, were analyzed. Nine additional benefits of automation are given, and a cost to benefits comparison are given. Comparison tables for the factors involved are included, with illustrative footnotes explaining the rationale for the comparisons. (Further information of the system may be found in LI 002 214.) (AB)