It's hard to imagine a more divine pianistic pairing than Martha Argerich and Mikhail Pletnev, who have just carried off a Grammy for their joint recording of Prokofiev and Ravel. Yet no other musicians treat the publicity game with such magnificent disdain. Argerich has given five interviews in 40 years, and if the famously moody Pletnev gives more, it's either under duress, or because there's something he burningly wants to get off his chest - and I've encountered him in both modes.
Tomorrow Pletnev will present the British premiere of his Quintet for Flute, Three Strings, and Piano. "I wrote it 20 years ago," he says with a regal wave of the hand. "I think it's not one of my worst compositions. Shostakovich's son heard it and said it had a similar effect to some of his father's works. Every composition has something positive, something negative."
But Pletnev is on a musical crusade, which he's about to bring to the Barbican: Sergei Taneyev. This late-19th-century Russian composer is terra relatively incognita, which in Pletnev's view is a grave injustice: "He was the key figure in Russian musical history," Pletnev informs me. "He was the greatest polyphonist after Bach.And look who his pupils were." Rachmaninov and Scriabin. "And Prokofiev, who said he learned more about composing in one hour from Taneyev than from all his other tutors at the Moscow conservatory."
But why, if he's so great, is he so little performed? "The compositions which have seized the world's attention have been consciously revolutionary, but Taneyev wasn't interested in revolution - he just wanted to create in the orthodox classical way. But I think history will now turn back to him. It's a bit like Bach; until Mendelssohn championed him, forgotten by the general musical public." Taneyev wrote several symphonies, Pletnev adds, but was only satisfied with one. "And he was a brilliant pianist, but wrote very few pieces." Namely? "There is a prelude and fugue." Which you play? "No. To understand his music you have to grow up a little. It needs maturity." Pletnev, at 48, is, presumably, approaching the requisite maturity.
In a memorable radio interview last year he declared that Western classical music was completed, and therefore "over": in his view there would be no more great works. Does he still adhere to that view? "Of course. Everybody knows that. There is a time to throw stones, and a time to collect them up." Come again? "Those words are from the Bible. Now we are collecting the stones. It means there is a time for everything. There is a time for ancient music, and a time for jazz." What music is it the time for now? "Probably pop." So when you compose, you are outside your own time? "Yes. I compose in the way I was brought up. In the language of Rachmaninov. That is how people of our generation feel. There were certain circumstances which helped classical music to be born, then it hit the heights. It's like a mountain range - you don't know exactly where it starts, but suddenly you are in the heights. Then you go on, then you are among smaller hills, then no more mountains - it is finished. For me the last great mountain was 30 years ago - Shostakovich's 15th Symphony."
Did the mountains come to an end because everything had been said? "Maybe." So what is there left for composers to do? "Me, I am still in the classical frame. But a new composer must study electronics and the art of synthesisers. Music composed by computer, and arranged with modern acoustic systems, sounds more impressive than music in the concert hall. If I listen to the recording of a Mozart symphony, and then to some rock when they know how to do it, or to the score for Star Wars - the classical recordings have less impact. New technology opens new doors." And closes old ones? "Not necessarily. But some things' time has gone."
For a man whose playing of Rachmaninov and Beethoven radiates the intensest love and commitment, all this sounds odd, particularly given the contented tone in which he announces it. So how does he see classical music's future? "I don't know. We need a new composer of genius to show the way. We shouldn't fear for its future. People will always be interested in the art of the past." But that's surely not the spirit in which he plays? "One must study tradition, but that is only scholarship. Music exists as sound, not on paper. It's born in your head. If not, you might as well play it on a computer. It would be the exact reflection of the score - and complete rubbish."
Pletnev once remarked to me that listening to his own recordings was "like seeing your ugly face in a mirror", so it's no surprise to hear him dismiss his latest (excellent) Schumann recording: "I can't say why, I'm just not turned on by it." What's next on his list? "There is no list. I have many proposals - things like concerti by Bartok - but I refuse. Maybe I will do some Mozart sonatas." The trouble is, he just doesn't like the sound of modern pianos - the ones he prefers are from the Thirties, like Rachmaninov's own, on which he's recorded some of that composer's works.
In his youth Pletnev was famed for his ability to memorise at sight and to turn in immaculate performances with virtually no practice: those faculties still seem in formidable shape, though he now spends half the year at his house in Thailand and his piano there spends most of its time shut.
I leave him taking the London Philharmonia through its paces in a Shostakovich symphony: with minimal gestures he gets maximum response. When he conducts Taneyev at the Barbican later this month, it will be with his beloved Russian National Orchestra, which he recently saved from an extinction threatened by the spectacularly dirty manoeuvres of a rival conductor who had President Putin's ear. Pletnev won't say a word about Putin, and when I seek his view of the rival conductor, he asks "Who is that?" with a provocatively blank stare. Pletnev and his band - who won a Grammy last year for their Peter and the Wolf starring Bill Clinton, Sophia Loren and Mikhail Gorbachev - may not bask in governmental approval at home, but in the eyes of the world they're the tops.
Mikhail Pletnev and the Russian National Orchestra Chamber Ensemble, play a benefit concert for the RNO at St Yegiche Church, Cranley Gardens, Tuesday 1 March (0800 652 6717). Taneyev and Rachmaninov, Russian National Orchestra with Nikolai Lugansky, Barbican, 30 and 31 March. (www.russianarts.org/rno/ontour.cfm)