Books and articles about Orson Welles are easy to find, but only a few treat his radio productions in much depth. The only book-length overview is Paul Heyer's The Medium and the Magician: Orson Welles, The Radio Years, 1934-1952. Below are some other ways to learn more about Orson Welles on the radio, including an essay from radio scholar Michele Hilmes and list of books and web sites for further reading.
An overview of Welles's career in radio, excerpted from Michele Hilmes's book, Radio Voices.
A bibliography of books and blogs about Welles's radio work.