If you are from the south of Italy and feel moved to insult your compatriots from the north, you call them "Germans". (The other way round, it's "Africans".) But what about the real differences between Italians and Germans? As Peter Conrad points out in this book, the Alps form more than a geographical barrier, and stereotypes of happy-go-lucky Italians and hard-working, obedient Germans endure. It is, of course, deeper and more complex than that. "In a discussion of Mozart's final symphonies, Claudio Abbado recently said that for Germans death pervades life and perhaps is life itself, whereas Italians regard death as an outsider and an intruder," writes Conrad, and there are plenty more plausible generalisations like that in this book. As this remark comes shortly after a mention of how Richard and Cosima Wagner were fascinated by and more than half in love with death  their tomb was completed before their house, Wahnfried  it is not otiose or impertinent.

Verdi and Wagner celebrate their 200th birthdays this year, and they're still not speaking. Verdi and/or Wagner begins in the Venetian garden where their busts stand: "The one who skulks in the bushes is Giuseppe Verdi. The other  his jaw set at a confrontational angle like a mountain ledge as he scans the horizon for detractors, or perhaps for devotees on pilgrimage to his shrine  is Richard Wagner."

You get the message pretty quickly: Conrad doesn't like Wagner the man very much. He would also appear to prefer Verdi's music. Wagner's is a drug; Verdi's a tonic. It is also, he says, more or less an impossibility to like both. Well, I, for one, am living proof that you can like both composers' works  but I would have to admit that I prefer Wagner's. (I exempt Die Meistersinger, whose nationalistic finale has come to seem, after the turns history has taken since it was written, positively creepy.)

Wagner the man, though, is another story. Conrad may have his thumb on the scales when he weighs up the characters of the two composers, but even allowing for distorting emphases, Wagner is thrillingly repellent. Indeed, one of the book's pleasures lies in the devastating attack on Wagner's character. I don't just mean the pleasure the reader gets from reading about Wagner's vanity; I also mean Conrad's relish in describing it, and then contrasting it with Verdi's almost saintly modesty. The description of Wagner's clothes makes him appear like a ludicrous pimp, whereas Verdi wore sober, anonymous suits. Verdi, responding to rumours that he was writing his autobiography, said, "I don't approve of this writing about one's life!" Wagner wrote Mein Leben  or rather, he dictated it, to Cosima, which makes it all worse.

One aspect of Wagner's character is, though  how best to put this?  underemphasised: that is, his anti-semitism, which was exceptionally vile and energetic. Verdi, on the other hand, composed "Va, Pensiero", a chorus sung by Hebrew slaves (there is a clip of me singing this on YouTube, believe it or not). Perhaps we know enough about Wagner's attitudes, and there is no need to dwell on them at length when plenty of books on this subject exist already. But this underemphasis does mean that you can't help feeling, sometimes, that Conrad has missed a trick: that there really is a big, deep problem with Wagner, and with liking him. It is possibly unfair of me, but I cannot help speculating about the most secret political allegiances of sections of a Wagnerian audience; when I sit among them, as I occasionally have, I can get seriously spooked. At which point one can reasonably ask: is that in fact part of the kick?

Still, this is a valuable work, not just because of Conrad's musical insights, but because of his grasp of historical context, which is really his stronger suit. His accounts of the contemporary  and historical  stagings of the two composers' works are exemplary, and useful; and the book itself is never dull.