No writer in my time has so dominated American music criticism as the deceptively receptive Alex Ross, whose bestselling book The Rest Is Noise, first published in 2007, fostered the delirious delusion that contemporary classical music is still part of civilised conversation. Starting with a richly illustrated blog and working up to an eponymous book, Ross drew creative links between serious and popular music. Music is music, he argues. If you like Björk, you might also like Boulez. With the sounds shuffled on your iPod while jogging in the park, you can hardly tell the difference. That means your taste is not so far apart from the next generation's - a warming reassurance.

A persuasive enthusiast, Ross writes for the New Yorker, a magazine that defines civilisation for much of the population on the eastern seaboard of the United States. A bold appointment aged 28 by the then editor, Tina Brown, in 1996, he has lost none of his freshness in the years since. This may be ascribed, in part, to writing fortnightly rather than, as he would have to do in the daily press, weekly or thrice-weekly - a hamster's wheel that can grind down even the most gifted of reviewers into somnolent fashioners of clichés.

Ross makes the most of his leisurely schedule, setting a broader, less Manhattan-centred, less event-driven agenda than did his British predecessors Andrew Porter and Paul Griffiths. The success of his first book has set him apart from the pack, making him almost above criticism. Ross is also credited with achieving the improbable: making new music an acceptable topic of dinner-table conversation.

This, his second book, consists of an abandoned preface to the first and a clutch of essays for the New Yorker. The qualities that make him a top-notch critic become clearer in concentrated reading. So, too, do his shortcomings.

Ross is an avowed buff. He loves music with a nerdish obsession and he wants you to love it as much he does. In one impressive essay, he takes us on a Baedeker's tour of the dance-song form the chaconne, from the revelries of Inquisition-era Spain, through the melancholic Renaissance Englishman John Dowland, down to the fratricidal Balkans, on to Bach and Ligeti and, finally, Led Zeppelin. The adjectives are mine - Ross makes no value judgements. For him, music is music, like it or not. He wants the reader to focus on the "classic" four-note bass - "the one that is heard variously in Monteverdi's 'Lamento della ninfa' and Ray Charles's 'Hit the Road Jack'".

Context, social and political, is sternly excluded, even in a panoramic essay on music in China in which the high-rise lives of the aspiring middle classes, consumers and star-makers of the musical future remain altogether invis­ible. His encounters with Chinese musicians yield the bizarre conclusion that "the creative climate, with its system of punishments and rewards, still resembles that of the late-period Soviet Union". Ross is too young to have witnessed the strictures of the Soviet era and so has no frame of reference in which to make that statement. On three visits to China, I have been overwhelmed by the subtle and subversive freedoms wrested by musicians from the system - something that was unthinkable in Soviet Russia.

Ross is most persuasive in his passions, which include the Finnish conductor Esa-Pekka Salonen, the mezzo-soprano Lorraine Hunt Lieberson, late wife of the composer Peter Lieberson, his college professor John Luther Adams (not to be confused with the better-known John Adams, of Nixon in China fame), Bob Dylan, Radiohead and late Brahms. Eclectic by design, he avoids taking sides, though the thoughtful reader will detect a mild preference for Strauss over Mahler, a distaste for histrionics and a peacemaker's urge to bring to an end the conflict between the classics and pop.

In his articles and on his blog, Ross purports to discuss all the music you could ever want to hear, but that is an illusion. Like every writer on music, he has likes and dislikes - though, unlike others, he does not kick against the pricks. No one knows what Alex Ross hates. That is a deficiency - a modest dishonesty, indeed - in a professional critic. He deceives by withholding his dislikes, apparently open to all forms of music and yet suppressing his distastes, thereby keeping his readers from knowing the true identity of a significant arbiter of taste.

Ross seems to want to be liked, yet great critics are measured more by their courage to be disliked, by their capacity for dishing it out and taking the inevitable backlash, by their willingness to face the music. Eduard Hanslick is better remembered for caustically hating Wagner in 19th-century Vienna than for tamely admiring Brahms. Harold Schonberg of the New York Times was at his best when laying in to Leonard Bernstein - often wrongly. Neville Cardus was not afraid to lambast Artur Schnabel.

The greatest critics do not mind being proved wrong. Alex Ross tries very hard to be right. Too hard, perhaps.

Listen to This
Alex Ross
Fourth Estate, 400pp, £25

Norman Lebrecht's most recent book is “Why Mahler?" (Faber & Faber, £17.99)