PERFORMANCE artist and avant-garde composer Laurie Anderson's association with Triptych has clearly been a meaningful one for both parties. Happiness, the first in her latest series of solo-performed works, received its world premiere at Scotland's three-city festival, and our interview - conducted by telephone from her New York studio - finds Anderson packing eagerly before a return visit. "I'm really looking forward to this, " emphasises Lou Reed's partner of more than a decade warmly. "What's the weather like? A bit chilly? Then I'd better pack my sweater."

Once again, Anderson will be presenting all-new work to a Scots audience, with her latest performance - The End of the Moon - forming "on the surface" a report of her time as artist-in-residence with Nasa. "That was about the strangest gig I've ever had, " she reflects. "Nasa called me up out of the blue to invite me, and I had no idea what they wanted. But neither did they. I think the idea at the beginning was that I'd do a multimedia project, but they have so many happening already.

"So, in one way, I've tried to represent where I went and what I saw - Mission Control, Hubble - but in another, it's more like a series of thought balloons. I didn't want to jam my experience into a story with a beginning, a middle and an end, where everything has to go somewhere, because so many things don't go anywhere. The story of Nasa is basically 'go fast, go up, go out' with a very futuristic orientation."

Described by its composer as "the most complicated thing I've done, although it looks the simplest", The End of the Moon is primarily narrative-based, and set to a backdrop of Anderson's music.

She will be playing her own specially-built violin - her favourite instrument alongside the saxophone, although she doesn't play the latter - which has been adapted to play lower notes, although Anderson is mercurial as to what form the strong electronic element of the show will take. "All of the equipment has disappeared into programmes, numbers, software, " she states. "So what I would need five trucks (full of instruments) to do a few years ago, I can now do with a couple of small items. The next time I'm hoping to use something that can fit in my pocket . . . I try not to worship technology, of course, but I love the freedom of it, and some of the astounding things it can do. Having said that, this show is about these non-linear stories - I don't think you 'feel' the electronics so much."

On the subjects of her stories, Anderson elaborates: "Some of them are about the people I met, and the experience of meeting them as an artist in a world of science. We had a lot more in common than I expected, because - as an artist - I'm not really sure what I'm looking for.

Neither are scientists; they just start with a hunch and keep their eyes open. The best example is Albert Einstein, who rejected some of his own ideas because 'they weren't beautiful'. What does that mean?

What was he looking for? Much the same as an artist, I'd imagine.

"Then I've written related stories.

About war, about contemporary culture, and what it's like to live in a world of media. That's kind of what all my work's about, but it's more apparent than ever in this show."

Despite The End of the Moon forming the second part of its own loose Triptych, however, Anderson is unclear as to exactly what form the finale will take. "It may involve dreams in one form or another, " she muses. "I'm thinking about what the difference is between dreaming and waking just now, because sometimes I'm not sure. "Basically, I only do things if they seem fun, if I think, 'I can't wait to do that'. As long as I don't associate it with actually working, otherwise I try to avoid it."

Laurie Anderson plays the Tramway, Glasgow, on Thursday, and the Queen's Hall, Edinburgh, on Friday.

* There have been a number of Triptych venue changes. Tonight's show at the Renfrew Ferry featuring The Earlies, Sam Prekop, Archer Prewitt and Micah P Hinson will now take place at Queen Margaret Union at 8.30pm. Tomorrow's Renfrew Ferry performance by The Fall and Uncle John and Whitelock is also at Queen Margaret Union, 8.30pm. Tickets are still available for all three shows. Free bus services will be available from the Renfrew Ferry to the new venues on both nights. Other scheduled events at the Renfrew Ferry are as yet unaffected.