Here are eight sweet posters from a 32-poster book, first published in 1965, Using Your Library: 32 Posters for Classroom and Library, by Mary Joan Egan and Cynthia Amrice. The posters guide baby-boomer children through the processes of research, book discovery, and borrowing.
In the 1960s, money provided by Congress through the Library Services and Construction Act enabled public libraries to expand their services. The act, taking a cue from the civil rights movement, was intended to extend libraries' reach into underserved rural and urban communities.
One poster below shows the ambitious range of types of materials that might be available to young patrons, including audiovisual items. In their exhibit about the history of American public libraries on the Digital Public Library of America's website, Hillary Brady and Franky Abbott point out: "Even before the rapid changes brought on by the computer age, libraries integrated things like microfilm and taped recordings into their collections."
I first saw these posters on the Tumblr of the University of Wisconsin-Milwaukee's Special Collections. (They have a Twitter, too.)