One of the questions that seems to perplex many university and special librarians is whether to move in the direction of centralizing or decentralizing the library's collections and facilities. Presented is a theoretical approach, employing location theory, to the library centralization-decentralization question. Location theory allows the analyst to examine economies of scale and the cost of overcoming distance simultaneously to determine the optimal location and size of university libraries for a given level of services. Specific applications for the Massachusetts Institute of Technology (M.I.T.) library system are discussed. (Author/SJ)