This bulletin on requirements by States and Territories for the certification of school librarians was prepared to provide a compilation of current certification regulations for school librarians and a summary of practices in formulating these regulations. The requirements for each State were obtained from either the State school library supervisors, or the State certification officers. For all States, the statements of certification requirements were verified by the school library supervisors, or the certification officers. As far as possible, the form and text of State certification requirements of school librarians were retained. Requirements in amount of general education and professional teacher education were inserted when lacking. Information on quantitative general and professional teacher education requirements, when not included by the States in their statements on certification of school librarians, was obtained from "A Manual on Certification Requirements for School Personnel in the United States," 1957 edition, by W. Earl Armstrong and T. M. Stinnett. Information on general State certification requirements in citizenship, health, age, fees, and courses in government and history (United States and State) is summarized in Table III. A bibliography of materials on the subject of State certification providing information on other pertinent regulations is included in the appendix of this bulletin. Nora E. Beust, former specialist for School and Children's Libraries, Library Services Branch, Office of Education, collected the original data for this bulletin in the spring of 1957. The data have been revised to May 1, 1958. Jessie E. Boehlert, Project Analyst, Library Services Branch, assisted in preparing the data. Appendixes present: State school library supervisors titles and addresses by States; State directors of teacher education and certification titles and addresses by States; and five tables. A bibliography is included. (Contains 7 footnotes.) [Best copy available has been provided.]