Where to find Mongolian throat-singers

With its exhaustive discographies, the single-volume first edition of this guide came like manna from heaven in 1994. Now we have two massive volumes, and we're twice as happy. Its growth reflects not only the dramatic expansion of the "world music" industry, but the realisation - in writers and readers - that all human life lies behind this glib high-street label. It also reflects something else: the understanding that music remains our hotline to cultures under threat from capitalist mass entertainment.

With its exhaustive discographies, the single-volume first edition of this guide came like manna from heaven in 1994. Now we have two massive volumes, and we're twice as happy. Its growth reflects not only the dramatic expansion of the "world music" industry, but the realisation - in writers and readers - that all human life lies behind this glib high-street label. It also reflects something else: the understanding that music remains our hotline to cultures under threat from capitalist mass entertainment.

But that's only my tub-thumping simplification. This multi-authored reference book leaves its readers free to draw whatever moral they please. In its US pages, rock makes no appearance, and neither does jazz: we get bluegrass, cajun, gospel, klezmer and native American - from which one infers a general thrust to chronicle musical traditions in their pre-capitalist state and to show music as an expression of embattled identity, of feeling and belief.

Where politics is the shaping force, the analysis is primarily political. Chile's nueva cancion is set in the context of pre-Pinochet struggles, with special emphasis on Victor Jara's tragedy and Inti Illimani's flight. The Australian chapter is devoted to the music of Yothu Yindi, Archie Roach and their Aboriginal fellow-artists - music as a cry of pain and defiance.

Where war has temporarily obliterated cultural life, as in Vietnam and Cambodia, the book looks back to the past before seeking its residue in the present. The Cambodian chapter focuses on the medieval dance styles that underpin musical tradition - in 1906, Cambodia's royal troupe was the hottest ticket in Paris.

The chapter on Vietnam offers an excellent survey of traditional styles still surviving. Confucian theory laid down eight categories of sound - silk, stone, skin, clay, metal, air, wood and bamboo - and five situations when music was forbidden (at sunset, during a storm...).

For me, the main fascination of this book is not the well-trodden areas, although - with massive sections on India and Jamaica, "the loudest island in the world" - these are dealt with impressively. I go to it for the stuff I can't find outside specialist magazines: the Cook Islands choir that "sings flat" or the mechanics of what is termed Mongolian "throat-singing". Overtone-singing is a more accurate description of this style, now making surprising inroads into Western musical life (a classical tenor was doing it at the Barbican recently), which carries the danger of burst blood vessels. It's nice to note that, in Mongolia, champion wrestlers do it best.

In neighbouring Tuva, music is pervaded by horse-culture, with less lucky animals playing a posthumous part (rattles are made from sheep's knuckle-bones in bulls' testicles). We're filled in on the way young Tuvans are splicing their traditional sounds with heavy metal.

To the vexed question of Western pop's benign/malign influence, the writers give a variety of replies. In many former Soviet states, it's eroding traditional forms more thoroughly than Communism ever did; also in China, as Stephen Jones explains. But this vast land is still bursting with musical life, in which "red and white business" - weddings and funerals - cause shawms to be brought out and the gong-frames wheeled into position.

There are limitations to the guide. To give more space to Cape Verde than to Russia reflects misplaced modishness. To lump Azerbaijan, Uzbekistan, Tajikistan, Turkmenistan, and Kyrgyzstan together as "Central Asian Republics" and dispatch them in eight pages reflects the fact that our knowledge about this crucial part of tomorrow's world is still scanty.

The Rough Guide discographies throw up humbling lessons for Brits. Time and again, the musicologists responsible for preserving ancient forms turn out to be German or French, while the most ubiquitous heroes are the Kronos Quartet - whose collaborations girdle the globe - and the indefatigable Ry Cooder, who brought us Buena Vista Social Club. On the other hand, Brits conceived this book.