To Daniel Barenboim, the connection between the prelude to Wagner's Tristan and Isolde and the end of the cold war is obvious. Equally, you would have to be a complete dunderhead to fail to see how the speed of harmonic progression casts light on the Oslo Israel-Palestine peace process. And, of course, music makes it “possible to imagine an alternative social model”.

Lawyers see the universe in a precedent, plumbers in a pipe, Barenboim sees it in music. All are bonkers and all are right. They are bonkers because they do not see the narrowness of their vision - most of Barenboim's claims about music can be made about any art. But they are right because that is how our imaginations work. We pretend our priorities are more important than anybody else's. That said, music is such a strange thing that Barenboim may be more right than the plumber. “Music,” he writes, “has a much larger world of associations at its disposal precisely because of its ambivalent nature; it is both inside and outside the world.”

A live musical performance begins, ends and then is gone for ever. Recording changes this, but not as much as we think. A CD of a performance is like a photograph; it is something, but it is not the thing itself. This one-offness reflects our own lives, we also end and are gone for ever. Theatre does this, of course, but music has one more ace up its sleeve. It is abstract. Sometimes it seems to be a mirror, reflecting our world, sometimes it seems to be a window on to a quite different world; sometimes, as in Wagner's Prelude, it seems to belong more to silence than to sound. No wonder it seems holy.

Barenboim tells the story of American Standard (AS), a plumbing supplies company, which ran a television ad for a lavatory accompanied by the Lacrimosa from Mozart's Requiem. People protested. AS apologised saying it did not appreciate the religious significance of Mozart's Requiem. It replaced it with Wagner's Tann-hauser Overture. This was, of course, equally blasphemous because what was offended was not one religion but the whole of musical art.

This book is at its best when Barenboim meditates on and explains the unique status of music. “I firmly believe,” he writes, “that it is impossible to speak about music.” But, somehow, he does. He describes brilliantly the way music works and the way in which its intricacies and logic justify his faith that everything is connected.

Barenboim falters when he strays into other realms. Perhaps because of his association with the late Edward Said - a man who was, to a rough approximation, wrong about everything - his cultural history can be a bit dodgy. Goethe was “one of the first Europeans to be genuinely interested in other cultures” - so all that Byzantine architecture and Arab mathematics never made it into the west then? And the political-musical parallels are pretty stretched.

But it is hard to be too critical of all this. Much of the book is taken up with Barenboim's account of the establishment of the West Eastern Divan orchestra, which brings together Israeli and Palestinian musicians. Nothing can be said against his heroism in this venture, nor against the heroism of the two Palestinians whose lives were turned away from conflict by music. Barenboim acknowledges the criticisms of his naivety in thinking such heroism can change the savage politics of the Middle East. But he points out that Israel's policies have achieved nothing in 60 years but mere survival. It is hard to believe a decent brass section couldn't do a better job than the incompetents, terrorists and hooligans who currently rule the region. The book ends with a selection of interviews and essays that return him to home territory - the actual making of music. Here, once again, he is at his best.

This is a messy, touching book. It reflects, often confusingly, a deep conservatism in Barenboim's temperament, an inclination possibly concealed from him by his partnership with Said. It establishes him, once again, as the most pure-hearted and, therefore, anguished advocate of the ultimate and lasting importance of art.

Everything is Connected by Daniel Barenboim
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