CNR Radio or CN Radio was the first national radio network in North America. It was developed, owned and operated by the Canadian National Railway between 1923 and 1932 to provide en route entertainment and information for its train passengers. As broadcasts could be received by anyone living in the coverage area of station transmitters, the network provided radio programming to Canadians from the Pacific coast to the Atlantic coast.

Radio drama is a dramatized, purely acoustic performance. With no visual component, radio drama depends on dialogue, music and sound effects to help the listener imagine the characters and story: "It is auditory in the physical dimension but equally powerful as a visual force in the psychological dimension." Radio drama includes plays specifically written for radio, docudrama, dramatized works of fiction, as well as plays originally written for the theatre, including musical theatre, and opera.