Youth orchestras in Venezuela: The music man Changing Lives: Gustavo Dudamel, El Sistema, and the Transformative Power of Music. By Tricia Tunstall. W.W. Norton; 320 pages; $26.95. To be published in Britain in April; £17.99. IN THE debate on the value of arts lessons in schools, one killer argument comes from a place that few know much about. Some are familiar with Venezuela's oil, natural beauty, high crime rates and comic-opera rulers. But the country is also home to el sistema, a network of youth orchestras founded in 1975, which has lifted innumerable children from overcrowded barrios and turned them into successful professional musicians. Its star graduate is Gustavo Dudamel (pictured left), who, among other things, is the music director of the Los Angeles Philharmonic. This month he begins an ambitious programme to honour the centenary of Gustav Mahler's death, conducting all of the composer's symphonies with both the LA Philharmonic and the Simón Bolívar Symphony Orchestra of Venezuela, his alma mater. The sistema concept is going places, with new pilot projects in Brazil, Scotland and other countries with inner-city deprivation. El sistema's near-mythological reputation has been reinforced by the proselytising enthusiasm of Claudio Abbado, Sir Simon Rattle and others, as well as some wishful thinking in rich societies that art can cure all ills. Its founder, José Antonio Abreu, has even been tipped for the Nobel peace prize. Yet there has never been a dispassionate study of Mr Abreu's method and results. Tricia Tunstall's new book is the first to document the process that Mr Dudamel describes airily as "creating miracles." An American music teacher, Ms Tunstall went to Venezuela with Jamie Bernstein, daughter of the late composer and conductor, Leonard Bernstein, and collected data and observations. She supports the grand claims with numbers. In a nation of 29m, she reports that some 370,000 children now participate in el sistema, singing and playing classical music for several hours each day after school. Ms Tunstall concedes that these figures are "slippery," as it is hard to get an accurate head count from remote Andean villages. The programme runs on an annual budget of $120m, most of it from the government. Ms Tunstall says the drop-out rate among el sistema students is less than 7% compared with 25% nationally. Although it is impossible to know whether el sistema alone creates good students or whether it tends to attract those who are naturally disciplined, fans of the system say standards are high and advancement swift, and that making music keeps kids out of street gangs. Edicson Ruiz, sent by his mother to a Caracas nucleo (learning centre) at 12, now plays the double-bass in the top-flight Berlin Philharmonic Orchestra. Gabriela Montero, who gave a solo concert with the Bolívar Symphony when she was eight, is now a star pianist. Besides cultivating musical excellence, Mr Abreu arranges to provide his charges with affordable instruments. Some have also learned how to craft them for themselves, allowing for an alternative profession. Mr Abreu explains to Ms Tunstall that he was inspired by a Paris-trained piano teacher in his boyhood town, Barquisimeto, who transcribed Mozart's Jupiter Symphony for seven pianos. "We were always playing for each other, and for other people, always enjoying it," he recalls. I never had the pressure of a severe, hard music teacher on my back. As a student in a Caracas conservatory, he rejected rigid convention in order to achieve what he calls "social transformation through music." The kids in his first youth orchestra were from the poorest of the poor. Eduardo Mata, a Mexican conductor, galvanised them with Latin American scores. But the driving force was always Mr Abreu, who persuaded politicians of all stripes to help expand the system across the land. "No one says no to Maestro Abreu," Ms Tunstall is told. It could not have been easy to ask hard questions about a man renowned for redeeming children, but Ms Tunstall tells a vivid story. Meanwhile Mr Dudamel, Mr Abreu's apostle, has brought the sistema to tough areas of Los Angeles, and another nucleo has opened in Brooklyn. Whether these schools can flourish without hands-on charismatic leadership remains to be seen. Glasgow and Rio will be watching too.