*VARIOUS PHOTOGRAPHERS* 186 Keystone Stereoscopic Views in 4 boxes with typed description sheets
|https://books.google.com/books?id=l2dBAQAAMAAJ|The Primary Set| Designed for kindergarten through 3rd grade children.
A remarkable glimpse of what educators thought children needed. Stereo cards were an early use of media in the classroom and brought the world closer...in 3 dimensions! An incomplete set, missing a few cards. Before 1920