She says she has chosen songs that are close to her heart, a heart that, at 53, has suffered the turmoils of what she calls "rough waters". Once married to Sir Peter Hall, the theatre director and founder of the RSC, for whom she quit America in 1980, Ewing came to be more famous for their marriage than for her singing. Now divorced, she describes their relationship as one of great creativity - a creativity that lives on in their genes (their daughter, Rebecca Hall, last year won the Ian Charleson Award for the best newcomer in a West End play, Mrs Warren's Profession).Ewing has always accepted her parallel music talents. She was keen to develop her classical ability, but also relished Dave Brubeck's music "alone in a room when I was eight." Years later, she became the first artist to perform a programme of Broadway hits at the Last Night of the Proms in Hyde Park, where she sang a programme of popular operatic arias as well as numbers by Gershwin and No?Coward "This other style has evolved and I take it seriously. I do it because I love it so much." By Maureen Isaacson Maria Ewing will be accompanied by her trio, James Pearson (piano), Matt Holme (drums) and Jeremy Brown (bass); for tickets to Broadway, Hollywood and Jazz: an Evening with Maria Ewing, call the Pizza Express Jazz Club box office, 10 Dean Street, London W1 (020-7439 8722; ) Wed to 31 May, £20. Geographically, we're just up the road from Afghanistan; musically, we're both nowhere and everywhere; and politically, we're somewhere rather interesting, given the violent return of the age-old fear of a clash of civilisations.

A posse of young Americans - plus musicians from Central Asia - are serenading the political establishment in Tajikistan, in an ornate oriental hall. Tajik musicians reply in their traditional musical language; the visiting ensemble counters with orchestral Bach, souped up with the tabla; there follows an increasingly sparky musical exchange, after which the leader of the visitors is granted honorary Tajikhood, and presented with the finest local lute that money can buy. For a bunch of (relatively) rich Americans to ride in, show off, and accept gifts, might be thought a shade risky in these edgy times, but their leader's answer, when he has got his breath back, engages head-on with present discontents.Yo-Yo Ma is a blend of Chinese, French and American cultures, and, five years ago, conceived a cross-cultural project of majestic symmetry and scope: a Silk Road for our times. The original medieval road stretched from the Mediterranean to Japan, and was based on trade in consumer goods: it was also the conduit for the secrets of gunpowder, mathematics and glass "I regard that as the internet of antiquity," says Ma. He'd noted the way that objects cropped up in surprising places: East African stones set into the back of a lute found in the ancient Japanese capital of Nara; a medieval plectrum decorated with an elephant, a Persian man, and a Chinese landscape. Researching the ancestry of his own instrument, the cello, he began to make stylistic connections between the Persian spike-fiddle, the Kazakh kobuz, the Tuvan horse-head fiddle, and the Chinese erhu, all of which are played in a similar way. It seemed a good idea, he says, to open up a new Silk Road, which followed the same geography, but whose trade was in music.Thus germinated a project designed to highlight those parts of the world that - until September 11 - had dropped off the West's mental map.

Nobody now needs telling about the importance of Central Asia, but shockingly few people - apart from the US military and Clare Short - can tell the Central Asian "Stans" apart. These countries have always been desperate: arbitrarily carved out of Russian Turkestan in the Twenties, they became dumping-grounds for the Soviet state's problems, with Kazakhs serving as guinea pigs for nuclear tests. Kazakhstan may be oil-rich now, but, like its neighbours, it's riddled with poverty and corruption, and that means with anger, too. Ma had planned to start the tour in Tashkent, until the State Department warned that it was unsafe. Yet 500 years ago, these states were the hub of a great civilisation, whose architecture and music were its crowning glories. "We want to give something back," says Ma, "to the people who in the past have given us so much."He accordingly enlisted the support of Central Asia's most discreetly powerful player, in the form of the Aga Khan. This hereditary leader of the Ismaili branch of Islam believes that today's burning issue is less a clash of civilisations than what he terms the "clash of ignorances".

It may come as a surprise, to those who think of this elusive 67-year-old and his family in terms of yachts, palaces and racehorses, to learn the scope of their humanitarian activities - largely through the UN - over the past 50 years. A champion of tolerant pluralism, he has initiated scores of medical, environmental and architectural projects in the undeveloped world, but Islam is his guiding thread.And while helping to rebuild Kabul, he has also decided to pour money and manpower into Yo-Yo Ma's scheme. Thanks to the Aga Khan Trust for Culture (AKTC), Central Asia's musical heritage may be reborn, and, through it, the Stans' emerging nationhood may get a boost. When you remember that Kazakhstan alone is the same size as the whole of Western Europe, you realise what is at stake: to these countries' mineral wealth you must add great strategic importance, both militarily and as the abode of Sunni Islam.But that rebirth is problematic, because the identity of the infant is in doubt. The Soviets spent time Europeanising the Stans' local music - putting nomad lutenists together to create vast orchestras - and in Kazakhstan, we were serenaded by the still-flourishing results. The Kazakh government proudly regards that as "traditional", but Ma's musicological advisers emphatically don't. In Tajikistan, we heard the nomad lute grotesquely accompanied by grand piano: chalk and cheese, so no again.No one should demand that "traditional" music stand still - it must develop or die - but some local forms are so "foreign" that it's hard to know what to do with them.