The Glasgow Improvisers Orchestra has been described as one of the best large improvising orchestras in the world.
It consists of around 20 musicians whose backgrounds range from jazz, folk and classical to pop, free improvisation, experimental music and performance art.
In the words of founder, saxophonist Raymond MacDonald, "we explore different ways of playing improvised music in large ensembles".
Instruments at their disposal include guitars, drums, sax, double bass, cello and flute.
In 2002 the Evening Times' sister paper, The Herald, said Raymond and his colleague, guitarist George Burt, had had an exceptionally busy year in 2002 but noted that the "main breakthrough was the formation of the Glasgow Improvisers Orchestra, a large group dedicated to speed-of-thought interaction that's visionary enough to lock horns internationally".
GIO has since gone on to release six CDs, perform all over the UK and Europe, and establish an annual festival in Glasgow, which provides a platform for improvising musicians and artists.
Factor in its programme of education and outreach activities that includes workshops, lectures and master classes, and it's not hard to appreciate the reach and influence of the orchestra.
For its 10th birthday festival, GIO has attracted such international talent as George Lewis, Evan Parker, Maggie Nicols and Jim O'Rourke.
Jim has worked as a guitarist or record producer with stars ranging from Sonic Youth to Joanna Newsom and Wilco, and GIO will perform the premiere of a new piece devised by him.
George Lewis has worked with Count Basie and Gil Evans, while Edinburgh-born vocalist Maggie Nicols, who established the Feminist Improvising Group, will collaborate with The Rope and Duck Company, which consists of GIO flautist Emma Roche, visual artist and vocalist Aileen Campbell, and double bassist Una McGlone.
The festival will also feature a rare appearance by the German free jazz supergroup, the Alexander von Schlippenbach Trio.
The Shetland Improvisers Orchestra will make its debut outside Lerwick, and GIO will perform new works as well as launch a CD featuring double-bass player Barry Guy and the poetry of Edwin Morgan.
Flautist Emma said: "Being part of GIO is a fantastic experience. I get to play with musicians from lots of different genres of music, which is something unusual for me as a classical flute player.
"I'm originally from Cork in Ireland and one of the things I love about Glasgow is the variety and vibrancy of musical life here. An awful lot of that is represented in GIO – classical, jazz, folk, pop, experimental musicians all coming together and finding a way of working together to create something unique.
"The thing I love the most about live music is that special connection you get between musicians on stage that brings something special to the music.
"The freedom of what we do musically is counterbalanced by the responsibility you have to your bandmates to create an environment where we can use our disparate skills to one aim."
SHE added that she is unlikely to have worked with Maggie Nicols outside GIO.
Emma said: "Maggie has been a major inspiration to me, as an improviser and as a female musician.
"I'm really looking forward to working with her again this year, especially as I get a chance to make music with her in a smaller group setting with the Rope and Duck Co.
"She had a big impact on me from the first time I met her, not only in a musical way, but also from the conversations we had about how she managed to make her voice heard as a female in the mostly male-dominated improv scene in the 1960s and 1970s.
"She's a fantastically committed and generous musician, one of Scotland's real musical treasures."
Like her colleagues, Emma believes there has been a 'definite change' in attitudes to free improvisation in Scotland.
She said: "I feel that it's a more acceptable activity for a classical musician to be involved in now.
"At the beginning it was almost as if we were involved in anti-social behaviour, but I rarely have to explain what we do these days.
"There's lots of improv in Glasgow apart from GIO. There are groups in Edinburgh and Shetland and there will soon be a module on free improv in the Royal Conservatoire of Scotland led by GIO's Una MacGlone.
"The landscape has changed hugely for us since the forma-tion of GIO. Improvisation is much more of a common discipline and it's been very exciting to be part of it all."
Raymond MacDonald spoke, too, of the festival as an "inspiring, welcoming and accessible three days of inquir-ing and life-affirming music".
A programme of discussions, workshops for children and opportunities to mix with the artists will all help GIO celebrate improvisation as a social, collaborative, accessible and unusual creative process.
n GIO 10th birthday festival, November 29 to December 1, CCA, 350 Sauchiehall Street, Glasgow. Log on to www. cca-glasgow.com for details.