Nowadays, the visualization of data is all the rage. It seems each new study or piece of research is turned into an image.
I’m not so sure this was as common in the 1930’s and 40’s when these visual aids were printed.
The series of 28 posters were produced under the supervision of noted librarian Ruby Ethel Cundiff for the Library School Course in Teaching the Use of the Library at the George Peabody College for Teachers.
These examples were salvaged by Char Booth from a throw-away pile at her library school in 2003 and were digitized by Gabriel Jaramillo at the Claremont Colleges Digital Library.