What is a radio play? In some ways drama is drama, whether in the theatre, on the television tube, in the cinema or on the radio. The main formal requirements of a dramatic text – plot, dramatic tensions and resolutions, the development of character and so on – are the same in any medium. For the actor a role is a role, a performance a performance, no matter how communicated. There are the same kinds of preparation, rehearsal, moments of truth. That given, one must try to define the differences: a radio play is a type of drama in which the main communicative instrument is sound. More elaborately, sound includes the words of the text; the differentiated voices of the actors and their interpretive performances; the sound effects; and the music – both bridges and supportive background. None of the visual codes of the stage is directly available to writer or producer: not the complete physical acting performance, nor costume, nor sets, nor the physical contiguity of the audience.