The functions, roles and responsibilities, and services of school media centers and public libraries at the local and state levels are succinctly discussed, and supportive functions and services provided by the State Library Commission of Iowa and the Department of Public Instruction are indicated. Also enumerated are recommendations for school media centers and public libraries regarding site location and facilities, bookmobile services, classroom visits to public libraries, funding, areas of cooperation for community-wide programs, and establishing good lines of communication. This is a revised edition of the 1966 publication, "Distinctive Functions of School and Public Libraries." (JPF)