It's Dolly, the bel canto sheep

Most composers, offered the opportunity to write an opera, would jump at the chance. After all, isn't opera the most exalted musical idiom, capable of wrapping all other art-forms in its capacious embrace?

Not according to the American composer Steve Reich, whose new "digital video opera" Three Tales is performed at London's Barbican this week. "Back in 1980," he recalls, "Frankfurt Opera and the Holland Festival asked me, 'Would you write us an opera?' I said, 'I'm delighted to be asked, it's very flattering. But no.' I simply didn't feel sympathetic to the form which, as it comes down to us, is about bel canto voices on the stage, and an orchestra in the pit. By that time, I had stopped working with the orchestra, and I wasn't drawn to the idea of acting singers, which was kind of fundamental to opera. I had no solution."

Yet in continuing to contemplate the "problem" of opera, Reich has more or less invented a musical form that, without being operatic in any conventional sense, nevertheless suggests another approach to the Wagnerian dream of the Gesamtkunstwerk (Reich himself lays no claim to such a high-falutin epithet).

Reich's new form has its genesis in one of his most celebrated compositions, Different Trains. Written in 1988 for Kronos Quartet, that piece used pre-recorded samples of people, including Holocaust survivors, reminiscing about train journeys both harmless and sinister. As he wrote at the time, "In order to combine taped speech with string instruments, I selected small speech samples that were more or less clearly pitched, and then notated them as accurately as possible in musical notation." This notated speech then generated the music for the string instruments, creating a densely poignant work that the critic Richard Taruskin describes as "one of the few adequate artistic responses in any medium to the Holocaust".

Although various choreographers have staged Different Trains, it was conceived for the concert hall. Nevertheless it set Reich thinking; as he now recalls, "In the process of working on Different Trains, a light bulb went on in my head. I thought to myself, 'If you could see people, not just hear them; and at the same time you could see onstage musicians playing and singing: ah-ha!' This was my way into music theatre."

At this point that Reich turned to a potential collaborator, Beryl Korot, an artist whose work with video dated back to the earliest, most experimental days of that medium. Given that Reich and Korot had been married for many years, it is surprising that they had not collaborated before. As Korot explains, "In the late-1970s, I had begun to find the image-making element of video work too limited, and when Steve was writing Different Trains, I was no longer working with video. But when he asked me if I would consider collaborating, I was beginning to feel that the way technology had evolved allowed a tremendous plasticity in creating images. The computer was just beginning to interface with video, so that film, photography and drawing could all combine. What Steve proposed allowed me to bring video art to a theatrical space, and that I found exciting."

The Cave, seen in London in 1993, involved Reich's ensemble of singers and musicians sharing the stage with a bank of five video monitors, on which Korot presented a montage of images. At its heart was a sequence of interviews with Palestinians, Israelis and Americans, who were asked to respond to various questions, including "Who for you is Abraham?" Reich's music used the interviews both as libretto, and, as in Different Trains, as a musical found object. As Korot says, "We had various contorted titles for what the work was, like 'documentary-music-video-theatre', but in the end, using 'opera' simply in the sense of 'work', we call it a video-opera."

Reflecting on the shared roots and antagonisms of Arabs and Israelis, The Cave has lost none of its relevance.

Now Reich and Korot have produced another piece that, verbally, musically, visually, even politically promises to be still more complex. Three Tales contemplates three episodes from the history of 20th-century technology: the disaster that befell the Hindenburg airship in 1937; the atom bomb tests that ravaged the Bikini atoll in the years after World War Two; and the cloning of Dolly the sheep in 1997.

Once again, Reich's music unfolds in close symbiosis with images and sounds emerging from Korot's screen (only one screen here, not five: for Korot, that in itself is a significant technological development). But Reich is not providing the "soundtrack" for Korot's work, any more than she is "illustrating" his music. In effect, text, image and music are indivisible.

Asked whether Three Tales takes an optimistic or pessimistic view of technology and its uses, Korot responds, "That is not the way we conceived it. We're asking whether there is humility or hubris among the people who are creating this technology." Reich endorses the point: "As artists and human beings, we, like everyone else, are beneficiaries of technology. My mother has Parkinson's disease, and one of the first medical implants that comes along may well be for Parkinson's. If it works, I would put her forward for treatment.

"There are benefits in technology, and it would be insane not to pursue them, but as in every field of science, there will be unintended consequences. Our piece is a series of cautionary tales."

'Three Tales': Barbican Theatre, EC2 (020 7638 8891), September 18-21