Philip Glass: Confessions of a chameleon

As a child, the composer Philip Glass worked at his father's radio- repair shop in Baltimore, which doubled as a small record store. It was there that he was exposed to a huge variety of music, from Schubert and Bartok to Hank Williams and Elvis. "I liked nearly all of it," he said years later. "People forgot to tell me some stuff was better than others."

From this early musical introduction, Glass's career has been informed by an eclecticism that has led him to seek out a dizzying range of collaborators across a variety of genres. "I discovered that by working with different people the music just comes out different," he tells me from his home in New York. "I always liked film, dance, poetry and various types of music, but I couldn't necessarily do those things myself, so working with these people brought me closer to their work."

He has found inspiration, he says, among those who "didn't quite fit in". Look no further than Moondog, the blind New York street musician famed for his love of Viking attire, whom Glass once roped in to conduct the Brooklyn Philharmonic Chamber Orchestra.

The esoteric minimalism of his early compositions in the 1960s meant they were rarely played in concert halls, and Glass had to support himself by working as a plumber and New York cabbie. "Sonic torture" was the headline on one review of 1969's Music in Fifths, which "sent a number of listeners racing out, their hands covering their ears". But the critical tide turned with Glass's first opera, 1976's Einstein on the Beach, a collaboration with the theatre director Robert Wilson, that was described by The Washington Post as "one of the seminal art works of the century".

Now 71, Glass has created more than 20 operas and innumerable symphonies, piano works, concertos and soundtracks, collaborating with such disparate figures as Brian Eno, David Bowie and Paul Simon, the novelists Doris Lessing and JM Coetzee, and the visual artist Chuck Close, much of which features on a forthcoming retrospective boxset.

Through such pairings, the founding father of minimalism has played a crucial part in breaking down the barriers between artistic mediums. But for Glass, it is less a crusade than a desire to do something different.

'Glass Box: a Nonesuch Retrospective' is released on 22 September

Philip Glass with...

Robert Wilson - Einstein on the Beach (1976)

"[The opera] Einstein on the Beach was a turning point in mine and [director] Bob's careers. It made us famous but it didn't make us rich. At the start we'd meet once a week, just to talk. Gradually, the idea emerged and we came up with a title. Then we worked out a structure – three ideas, four acts. Then Bob started doing drawings as a way of proposing the visual elements. I began writing music to the pictures, then Bob began staging the action to the music.

"It was probably the most famous financial disaster you could hope for. Back then we didn't understand that even if you had a full house you could still lose money. It was another four or five years before I could give up my day jobs. Bob and I had run up a debt of $100,000. I learnt then that fame and fortune are not connected."

Doris Lessing - The Making of the Representative from Planet 8 (1986)

"The Making of the Representative from Planet 8 is part of what Doris calls her sci-fi series. I knew the book well, and I wrote her a letter and told her I wanted to use it as a basis for an opera. She thought it an interesting idea and said we should meet when I was in London. I wrote back to say I'd be there next week. When we met she asked why she should let me set the story as an opera. I said, 'Mrs Lessing, I can say things in music that you can't say in words.' There was a silence... then she said OK. She loves the theatre – she came to see Satyagraha [Glass's opera on Gandhi's years in South Africa] – but she's not a theatre writer. She wasn't used to making changes. But we got there in the end, and I think she liked the result."

David Bowie and Brian Eno - Low Symphony (1993)

"In the early 1980s I was asked to do a symphony and I had the idea of taking material from another composer and making a piece out of it. I said, 'Well, if Brahms can use Haydn, why can't I use David Bowie and Brian Eno [Bowie's collaborator on the 1977 album Low]?' I knew their 'Berlin Trilogy'; they were interesting records.

"Those were the days of double-sided LPs and I was interested in resetting the B-side. I never knew who did what on it and they never told me but I knew that a born composer and melodist had worked on it. I took a theme as Brian or David had composed it and extended it into a 12- or 14-minute movement. It was meant to be a seamless continuation. There was a certain type of orchestration in the way it was recorded and I used that as a guide.

I like the idea that talented composers can exist outside of conservatories. [Eno and Bowie] were meant to be rock'n'roll musicians, but the fact is that they knew how to compose. They're extremely gifted."

Martin Scorsese - Kundun (1997)

"I first heard about the film Kundun through its writer, Melissa Mathison. She was well known for having done ET. She told me she was working on a piece on the life of the Dalai Lama and since I already knew Marty [who was directing it], I got his number and called him up. Soon after I went to see him and said I had to do the score. He asked why, and I said I knew just how to do it, that the music had to be a bridge between the West and East. I then told him the musicians I'd work with and he started to get interested. Usually, it requires agents and directors to negotiate these things and it can take forever. In this case, he just said OK.

"After the movie came out, the score became a concert piece but for me the images and music are connected in a way that I don't care to disconnect them. We had a few disagreements but Marty always won. He would always let me make my case, then would simply say no. In the end it was his movie. I think we got along fine."

Leonard Cohen - Book of Longing (2007)

"I got in touch with Leonard about working together in 1999, and we started a day after our first meeting. He would come around with page after page of uncollected poetry, just pieces of paper in a pile. He would read out the poems while I took notes.

"We had several meetings, but then there was a five-year break when he was in a [Buddhist] monastery, after which we went forward with the idea. By this time, all those bits of paper had become a book.

"I wanted to write the music in the way we read poetry. When you read a book of poetry you dip into it here and there and at a certain point you realise you've read the whole book. I also wanted to cover the thematic variety of the poems, from the dharma poetry and love poems and ballads to these little, short things I called limericks. I loved those.

"It was a good division of labour. He did the words, I did the music. I said, 'You're a musician, don't you want to do the music?' He said, 'I want to hear what my poems sound like with your music; I know what they sound like with mine.' That was such a sensible thing to say.

"I had actually written to him 25 years earlier about setting some of his poetry to music, but he never got back to me. I reminded him about it, and he said he remembered my letter but didn't say any more. That's just the way it is with artists."