A much yearned-for sunshine break in southern Spain - the rain in Spain falls mainly, that's a pain, this weekend -- means that I shall miss the opening tomorrow of Going Dark at the Young Vic, but I hope to catch it when I return. For this is the latest from Sound&Fury, who were last seen along the Cut with their extraordinary Kursk, the show set on board a British submarine heading towards a stricken Russian submarine in the Barents Sea.

It was one of the outrages of recent Russian diplomacy and foreign affairs that Vladimir Putin, newly re-elected President of Russia, refused all offers of assistance from NATO and other countries, and that his countrymen perished so tragically in their watery coffin.

Going Dark sets out to explore a similar, deeply allegorical version of sensory deprivation: an astronomer is going blind in a planetarium while trying to make contact with his six-year-old son. It promises to be another sound and darkness special from the company that launched with War Music, Christopher Logue's great poem, recited in a total black-out at the BAC.

The playwright on Going Dark, Hattie Naylor, has responded as much to the technical input on the show as to the “research” contribution of co-director Tom Espiner’s six-year-old son, Jack, who was recorded while asking some questions based on his innocent view of the universe.

One of the most striking things about Kursk was its sheer technical virtuosity. It represented a way of employing modern technology in theatre very different from, say, the CGI wraparound effects in a Trevor Nunn production, or a William Dudley design, or the clumsy juxtaposition of cinematic effects or video sequences we get these days in Shakespeare or musicals.

Sound&Fury seem not to buy into the current fetish of cinema as theatre, but they are involved in a discussion right across theatre at the moment, as to how the technical stuff doesn’t become a sort of exoskeleton which forces the actor into a straitjacket.

And it's not terribly complicated, or even expensive. On Going Dark, the Espiner brothers (Mark and Tom) and composer/sound expert Dan Jones are using a mere laptop, a Mac Mini, a tiny box of tricks, which stores video, sound, the lighting cues, everything. That’s the whole show… plus the speakers, the scaffolding, the black drapes and the actor, John Mackay, recently a member of Michael Boyd's RSC ensemble.

In his book Eye and Brain, the late neuro-psychologist Richard Gregory says that “the brain is less understood and more mysterious than a distant star.” As in Gregory’s writing, and in that of Oliver Sacks, Sound&Fury are really conducting an investigation into the human spirit by other analytical means, so that in the miracle of the universe, and in a meditation on our sensory perception of it, we find clues to the human condition and learn about ourselves.

That's the idea, anyway. You wonder what Harley Granville Barker, radical visionary of the early Royal Court with Bernard Shaw, and all-out enemy of what one of his characters called the "tinselled" theatre, would have made of it.

Richard Nelson's new play at Hampstead, Farewell to the Theatre, which opens tonight, shows Granville Barker, played by Ben Chaplin, at the key moment in his career when he abandoned practical work for theorising. He's long been credited with being the guiding spirit of both the RSC and the National, and Nelson has unearthed in the programme a fascinating essay on him written by the late theatre director David Jones, whose production of The Marrying of Anne Leete at the Aldwych kick-started a new interest in the playwright.

Granville Barker's Waste and The Voysey Inheritance are two of the greatest plays of the last century, and both have been done by our major companies. I also like The Madras House, which William Gaskill directed on the Olivier stage with Paul Scofield in the lead.

Gaskill also supervised a staged reading (in 1992) of Farewell to the Theatre, the short Granville Barker play whose title Nelson has purloined for his own piece. The title is so evocative, and Granville Barker's reputation so high among theatrical insiders, that Hampstead has already attracted the likes of Trevor Nunn, Janet Suzman, Jennifer Saunders, Roger Lloyd Pack and Harriet Walter to its preview performances.

"What are you doing here?" Harriet asked me, accusingly, last night, as I joined the last preview throng. I muttered something about a pile-up in the fixture list and going on holiday. She wasn't impressed, but she did introduce me to her charming new husband. I forebore to ask, now she's a Dame, where does that leave him? Plain mister, I guess.