From a post on Modern Soundling
In the next few weeks, I'll be delving into the world of Gormenghast. The poet, artist, and novelist Mervyn Peake created this world in three books: Titus Groan, Gormenghast, and Titus Alone. Brian Sibley recently dramatized the whole series for the BBC, including a new book by Peake's widow Maeve Gilmore, continuing the story. 
But what happens when one cultural work is transferred into another medium? It happens very often. The two terms used are adaptation and dramatization. I'm not sure if these two terms mean the same thing, or contain distinctions. In the Audio Drama Wiki, we label everything a “dramatization” that is a radio version of a thing from a different medium. I chose the term arbitrarily.
Stage plays can also be included as dramatizations, when they are altered for radio. Interestingly, this distinction is not widely made when radio plays are adapted for the stage. In such cases, the radio play is typically ignored and treated as an inferior prototype. There are many examples of how this is clearly misconceived but I won't bother with that right now.
When discussing an adaptation, there is an inherent tension between people who like the original thing, and people who like the adapting thing. I get annoyed by these instances, because both sides routinely don't know what they are talking about. Let me dispel some confusion.
There are two possible courses of action for an author who uses a work to create another work. The first course is where an author translates that original work from one medium to another, changing where necessary, but ultimately remaining faithful to the thematic concepts behind the original work. That's a good adaptation.
The other course is where an author takes inspiration from something, maybe even taking direct elements of story or character, and creating a new thing. When authors take this course and simultaneously change mediums, people often mistake it for an adaptation. It is not an adaptation when the basic thematic elements, the artistic intention behind the original work, is not translated intact. It's something else, and I don't have a word for it. An “inspiration”? I dunno.
An example of a faithful adaptation is Harold Pinter's screenplay for The French Lieutenant’s Woman. In the original novel, John Fowles tells the story of Sarah Woodruff and her relationship with a married man. On the surface, the story is fairly straightforward. But a faithful adaptation could not merely dramatize this surface story and be true to the author's intentions.
Those intentions are revealed not in the narrative but in the author's voice in conveying the narrative – Fowles is everywhere in the text, making asides, pointing out things about 19th century life, inserting himself as an authorial voice while simultaneously keeping the story going. The whole point of the novel is that it is not just a linear narrative, but a narrative that the author constantly compares and contrasts with modern life. The style of the thing is intrinsic to its meaning, and yet the style is the stuff of pure literature – a fabric of words and nothing else.
The screenwriter is therefore tasked with finding a filmic equivalent to Fowles' style. If the screenwriter doesn't do that, then it's not an adaptation. It would instead be like all of those random dramatizations of Jules Verne novels – the plot structures are superficially the same, but each version mints a new meaning (or at least abandons the original intention) in favor of whatever whims or fancies or corporate marketing the producers have in mind. So what did Pinter do?
Harold Pinter's screenplay solves the style problem by adding a new narrative. He creates a new set of parallel characters that are playing the characters that Fowles has created in a movie. It's a movie-within-a-movie, and a stroke of simple genius. The original narrative continues as planned, but is supplemented by the story of the making of the film and the two lead actors' relationship with each other. The comparison and contrast is there, the voice of modernity is there, and Fowles' intention is there.
Of course, there is sometimes room for debate as to what an author's intention is or was. That's fair enough. But while we might reasonably debate what Fowles' ultimate aims are, we can surely agree what is aims are not. They are not exclusively the surface narrative.
How does this relate to audio drama? Radio has, from the very beginning, been the domain of adaptation, I haven't thought much as to why. But a significant amount of BBC output is devoted to dramatizing classic literature, and if we are to consider these things not merely as facsimiles of novels and stage plays but as radio in and of themselves, then we have to have a basic criteria for analyzing them.
The author of a classic serial is not the author of the source work. It is the playwright who adapts it for the radio and writes the script. That's why each entry in the audio drama wiki of such a play says “Gormenghast is a radio play by Brian Sibley, based on the novel by Mervyn Peake”. The radio play is not by Peake. It's by Sibley. Once we are mindful of this emphasis we can consider these questions:
What is the intention of the author of the source work?
How has the author of the radio play rendered this intention?
What is the audio equivalent of the original author's style?
Is the radio version even an adaptation at all, or is it merely inspired by the source?
And now I have to re-listen to all the Gormenghast adaptations and try to answer these questions!