The Shared Purchase Program, now in its ninth year, was implemented mainly to prevent unnecessary duplication of expensive, low-use materials among the nine campuses of the University of California. Stanford University also has been a full participant for the past six years. Although shareability of materials is an important consideration, the Program permits the acquisition of manuscripts and archival collections. Funding is provided by taking a percentage of the total University library materials budget each year before campus allocations are made. The Program is considered a success by its participants, in spite of problems of methodology and access that remain to be resolved.