Tom Stoppard Gives "The Dark Side of the Moon" a Makeover Mark Allan/BBC From left: Iwan Rheon as The Boy; Adrian Scarborough as Fat Man; Tom Stoppard; Amaka Okafor as Emily McCoy; and James Robinson, a producer, during the recording of "Darkside." In his 2006 hit play, "Rock "n" Roll," the British playwright Tom Stoppard examined the relationship between music and politics, shuttling back and forth between England and Czechoslovakia over a 25-year period. Now, in a new work, a one-hour radio play called "Darkside," he has narrowed his focus to a single famous album, Pink Floyd's "The Dark Side of the Moon." Commissioned by the BBC to commemorate the 40th anniversary of the release of a recording that has sold more than 50 million copies worldwide, "Darkside" was broadcast in August and this week will be released in CD form (Pink Floyd Music). Mr. Stoppard has stripped the record of most of its lyrics, writing his own text to be recited over the original music while intermittently drawing on the band member Roger Waters's words to provide commentary on what has just happened. The subject matter of "Darkside" will be familiar to anyone who has ever taken a college course in ethics or moral philosophy. The cast, which includes Bill Nighy and Rufus Sewell, acts out familiar thought experiments from that realm, like the Prisoner's Dilemma and the Speeding Trolley, with plenty of jocular asides and subtle jokes inserted. In "Rock "n" Roll," Mr. Stoppard, now 76, showed a formidable familiarity with the pop music of the "60s and "70s, referring to the Rolling Stones, Jimi Hendrix, the Beach Boys, the Grateful Dead, the Velvet Underground, the Doors and Queen. In a telephone interview last weekend from his home in England, he talked about the genesis of "Darkside" and his catholic taste in pop music. Here are edited excerpts from that conversation: Q. What did you initially see as the challenges to adapting this record to play form? A. I had absolutely no idea what to do with it, which I guess is normal. I was very pleased about the whole thing. It's very common for people to recommend something to me because they're going on what I've already written, when, what really is the case, is that you want to write about something you haven't written about, in ways that you haven't done before. Q. Did it seem to you that having to work from the record, and in a fixed time slot, was constraining? A. For my whole career, from the very beginning, I think, I've liked being given parameters or frontiers or directions. You know, "Rosencrantz and Guildenstern are Dead" is an example. I had to work inside Shakespeare's play. Working inside Pink Floyd's album is the same syndrome really. Q. In the end, "Darkside" strikes me as a kind of comedy about moral philosophy. Would you agree? A. I think that's fair enough. I was using things from my own reading, things I've been collecting for the purposes of a play for years and years. This is already something I wanted to write about, and the album felt to me like a bunch of songs that were saying, "Yeah, come on, use up some of that stuff, and don't keep saving it for some three-hour play." Q. Did you feel any trepidation about largely erasing Roger Waters's lyrics? A. In point of fact, I had less trepidation about that than I did in writing over the music. I know David Gilmour somewhat better than I know the other members of the band, and I was feeling diffident about the possibility that David would mind if the music was pushed into the background, half-heard, in order for my words to take the foreground. So I called him up, and he was completely O.K. about that. He said, "Go ahead, fine." Let's face it, "Dark Side of the Moon" is not vulnerable to being obscured by a radio play. Q. We know from your play "Rock "n" Roll," with its references to Pink Floyd, that you have an affinity for the band. Why it rather than another of the many groups you mention in that play? A. I just think they're a really exceptional bunch of people. I think "The Wall" is a masterpiece, and when I made a film of my "Rosencrantz and Guildenstern," I actually used a track from "Meddle" called "Fearless." What I'm trying to say is the BBC were seven-eighths of the way there, without knowing it, when they contacted me. I guess because of the play "Rock "n" Roll," they probably thought I was a good person to approach, and they were right. Q. Can you talk about your own history with "The Dark Side of the Moon"?