The critical attention paid to radio drama has dwindled in almost inverse proportion to a steady increase not only in quantity but, less expectedly, in quality – though Britain has become one of the very few countries where this entirely distinctive dramatic medium is still seriously practised. As Head of BBC Radio Drama from 1963 to 1976. Martin Esslin was instrumental in developing the form, and his article in TQ 3 in 1971. ‘The Mind as a Stage’, in which he summed up his own ‘aesthetic of radio’, provides the starting point for the present article: but its authors believe that the very strength of Esslin's own artistic beliefs and authority limited his understanding of the less ‘artistic’ output of radio drama, and that it is in this area that some of the most notable of recent advances have been made. Their article thus examines not only the development of radio drama since 1971, but the way in which its changing ‘codes’ have altered the relationship between play and listener: and it analyzes two distinctive uses of the medium – to create what they call ‘alternative histories’, and a sense of ‘fragmented space’. Frances Gray, herself a radio playwright, has recently published a study of John Arden in the Macmillan Modern Dramatists series, and presently teaches at the University of Sheffield, from which Janet Bray has just received her M.Phil. degree for a study of radio drama in the 'seventies.