Oh, for the days when criticism mattered. And really mattered, to the artists being criticised. For instance, Adorno had some hard words to say about Stravinsky, and as a result Schoenberg wrote to the critic HH Stuckenschmidt: "It is disgusting … how he treats Stravinsky. I am certainly no admirer of Stravinsky, although I like a piece of his here and there very much – but one should not write like that." It is also possible that Sibelius destroyed his eighth symphony partially because he had read or heard about a particularly destructive attack on him by Adorno. (I find this hard to believe.)

But the point was that Adorno was listened to. The remark of his that most people are familiar with – that after the Holocaust there could be no poetry – is these days cited as an example of how an intellectual can get things wrong, but this is to miss the point: Adorno was incredibly sensitive to the notion of morality in art, of how the manipulation of emotions by cheap music, or cheap art, or even the exploitation of great art, could lead to the barbarity of Nazism, and the acquiescence of the masses.

Adorno wrote about everything, really, but what he wrote most about was music. He knew what he was talking about: he had entertained attainable ambitions to compose, and been taught by Alban Berg. When Thomas Mann, in exile, needed to have a serialist composer in Dr Faustus, it was to Adorno he turned, and his contribution to the book was invaluable. Schoenberg, exiled a few miles up the road at the same time, was seriously miffed for years that he hadn't been asked – understandably, since he had invented the atonality of Mann's composer. But there was something Adorno could bring to the table which Schoenberg couldn't. As George Steiner put it, "what Adorno contributed [to Dr Faustus] was not only the hard-edged technicalities of compositional and instrumental processes, but his own radical perceptions of what it is to compose music under pressure of previous musical history and of social crisis."

Of course, in this country, we are largely resistant to the ideals not only of the higher criticism – not, when you consider some of the arid nonsense that occasionally creeps out of the academies, automatically a bad thing – but of the very notion of atonal, or 12-tone, music (which is now roughly a century old. I wonder when one of Radio 3's disc jockeys – there's no other term for them these days – last broadcast a work of this genre. I don't count broadcasts of concerts. And when did the station last play any Zemlinsky, one of the composers written about here? And he wasn't even a serialist). And this scepticism really is a bad thing, a small but significant contributor to the mess we're in at the moment. A mind as alive to fine distinctions as Adorno's would have spotted and railed against the ceaseless mendacious drivel of our politicians every time they opened their mealy mouths. As he once said elsewhere: "It starts with the loss of the semi-colon; it ends with the ratification of imbecility by a reasonableness purged of all admixture." Which is why in a sane and just world someone would be paid to go to Verso's offices in London W1, and shower its employees with rose petals every day, simply because they are Adorno's publishers here.

In a sense, it doesn't matter too much which book of his you get Minima Moralia, which is very broad-ranging, might be a good place to start, but Quasi Una Fantasia is as good as any. His criticism is a tool which can work any number of materials; not just modern music. He may have said what he said about post-Holocaust poetry ("There are no words for the noble, the good, the true and the beautiful that have not been violated and turned into their opposite"), but his language, dealing with the transcendent, itself becomes at times transcendent, beautiful in its hard-edged, uncompromising way. It's not easy reading. There are times when I feel as though I have not the faintest idea what he's saying. But then there is no German word, I gather, for "pretentious".