Children's librarians were active radio broadcasters as early as 1922, when American commercial radio was just beginning. As they utilized the new technology of radio to promote reading, literature and outreach, they transferred techniques and materials already familiar from their work in neighborhood libraries. This article documents children's librarians' early innovation by examining their engagement with radio broadcasting, between 1922 and 1941, and illustrates how they transferred existing professional practices to new communications technology opportunities--something youth librarians continue to do today. (Contains 11 footnotes.)