The U.S. Office of Education undertook this study at the request of State supervisors of school libraries for data to aid school administrators and librarians in determining the cost of operating libraries. The findings of this exploratory study have been gathered from a limited sampling of a group of selected high-school libraries. It is hoped that they will be of some value in (1) establishing quantitative costs of school library operation and (2) indicating a method which may be used as a basis for future studies. Appended are: (1) Time sheet; (2) Manual of instruction; (3) Statistics sheet; and (4) Questionnaire. A bibliography is provided. (Contains 5 tables and 18 footnotes.) [Best copy available has been provided.]