The Making of Star Wars for Radio: A Fable for the Mind's Eye is a half-hour radio documentary on the adaptation of the original Star Wars movie to radio, which I recall listening to (at least part thereof) and enjoying many years ago. Some interesting insights into the creation of the soundscapes, directing for voice and so forth, but what surprised me was that the director was John Madden, who later would go on to direct one of my favourite movies, Shakespeare in Love.
Reading up on the Wikipedia entry for the series, more interesting facts emerge like the fact that Lucas sold the rights for one dollar and granted use of the original sound effects and music, or that the radio play - totalling over six hours - included much of the backstory that never made it into the film (though some, like Luke witnessing the opening battle over Tatooine via binochulars, did make it into the novelisation as I recall).
The reference to the "the mind's eye" is cute, given the name of the earliest original Star Wars novel, but of course appropriate as radio plays, when well done, do open "the mind's eye".
Neil Gaiman has said that audio plays are his favourite form to write, and that he would do it more often if only he could support his family that way. J Michael Straczynski in his Complete Book of Scriptwriting propounds that "creatively speaking, radio-drama is probably the one medium most dependent on the writeer's craft". And of course the Hitchhiker's Guide to the Galaxy started off in radio.
Will have to give it a go one day - just to see what works, and what doesn't, compared to writing prose, plays or teleplays. One immediate problem is how best to convey action: by sound effects (Sound of gun firing), by planting clues in the dialogue ("Arrgh! You bastard, you shot me in the arm!"), by voiceover narration ("I tried to move out of the way, but the bastard was too fast and the bullet hit me in the arm, splattering blood over the linoleum floor boards"), a mix of some or all of these? Something else entirely? When is one method preferable to another?