This case study applies a mathematical model to the Illinois Library and Information Network (ILLINET) Rolling Prairie Library (RPL) System. Given certain dimensions, parameters, and operating policies of a library network, the model calculates probability of satisfying a request, average processing time, average total and unit costs, and average processing loads through the network. The study describes quantitatively how RPL headquarters attempts to satisfy a request, and considers the parameter requirements of the ILLINET model and data from a 12-week sample. It analyzes present policy, focusing on the effects of changes on fill rate/processing time, and the impact of filmed card catalogs on performance. Value oriented policies are defined in terms of strength, time, and compromise, and are analyzed for effects on systems performance. The study recommends: (1) requests waiting for missing or reserved documents be held only seven days and referrals be made automatically on a specified route to decrease average processing time; and (2) the filmed card catalog be used early in the referral route to decide participating libraries and query order. Essays on suggested routing of requests, data collection, and request classifications are appended. (KP)