The principal conductors of European orchestras are responsible, in general, only for the music. In this country, music directors must shoulder other tasks, taking a prominent role in their orchestras' community relations and in fund-raising. When Christoph Eschenbach took over the leadership of The Philadelphia Orchestra in 2003, he could already draw on much more experience in those fields than his immediate predecessors possessed when they arrived. As he remarked at that time, "With eleven years in Houston, and nine in Ravinia [the Chicago Symphony's summer festival], I learned very much about the American system‹about how organizations like orchestras work, and the role of a music director. And it's of course an enormous benefit for me, at The Philadelphia Orchestra, not having to learn the basics and all the implications which are combined in this job. I swim actually in the same water, and I'm not surprised by things, not overwhelmed by things."

The "things" in question frequently include greeting a hundred sponsors at the end of a concert. "I'm absolutely used to that," Eschenbach said, "and I like to speak to people. I like the idea that the music director is very much involved in fund-raising‹explaining to the possible donor why it's a joy to give money to the organization, and why it's a joy to support music, and why it's important for the future that music keeps this thing alive." His actions have been as good as his words. One achievement for which Eschenbach's five-year tenure will surely be remembered is a great deal of progress in what he calls "raising the invisible curtain": New constituencies have been actively canvassed, and the concert audience now looks much more diverse, with many more young people among its ranks, than it did before. Meanwhile, thanks to constructive collaboration between the maestro, the musicians, and the administration in the Orchestra's Media Institute, a ground-breaking relationship with the distinguished Finnish CD label Ondine has already resulted in impressive recordings of music by Mahler, Tchaikovsky, Bart‹k, and others. Nor should Eschenbach's instrumental role in stimulating major financial contributions from the Annenberg Foundation and others be forgotten.

But in the historical view, and from an artistically if not societally broader perspective, it is what the seventh music director has brought to The Philadelphia Orchestra's actual performances that must assume the greatest importance. He inherited, let us remember, an orchestra in wonderful shape. Profiting from the opportune retirement of several senior players, Wolfgang Sawallisch had made a number of excellent additions to the personnel roster. Eschenbach for his part has, in his five years, appointed some 20 new players, including Jennifer Montone and Carol Jantsch, the first women to occupy the Orchestra's principal horn and tuba chairs. With all this, it certainly seems to me‹and I have heard the Philadelphians perform very frequently with all of Eschenbach's most recent forerunners‹that the celebrated orchestra is probably greater now than at any time since I first heard it live, under Leopold Stokowski's magic batonless hands, in 1964.

It is, however, in the style of his music-making that Eschenbach's contribution has had the most striking effect. To generalize wildly, if the Muti years are remembered above all for that conductor's charisma, stylistic insight, and intellectual intensity, and Sawallisch's for an unswerving devotion to clarity and precision, it is wide-ranging imagination and the fearless taking of interpretative risks that have most vividly characterized the period now coming to an end. This has been true both of the music Eschenbach has chosen to program and of his way of performing it. He has instituted ambitious cycles like the multiyear traversal of the Mahler symphonies currently reaching its climax with the "Symphony of a Thousand," as well as a fascinating "Late Great Works" series in 2004-05, and this season's Bernstein Festival. He has maintained a lively schedule of commissioning and programming new music, including the world premieres of a dozen works by composers including the celebrated Maw, Gubaidulina, and Rorem, as well as the U.S. premieres of substantial works by Henze, Knussen, MacMillan, Pintscher, Dalbavie, and Rihm. The local creative scene has benefited notably from Eschenbach's willingness to commit himself to ongoing support of the composers he admires, with commissions to Philadelphia's own Jennifer Higdon and Gerald Levinson.

Certainly the new works have not in all cases been to my personal taste, but that is fair enough. Every music director is entitled to his own vision, and a vision is precisely what Eschenbach's very first season's program immediately and stimulatingly proclaimed, with its substantial overview of the works of Messiaen, and its innovation, after several orchestra concerts, of Postlude Recitals utilizing the music director's pianistic gifts. Also from the start, any unfamiliar or especially challenging repertoire found Eschenbach coming on stage beforehand, microphone at the ready, to talk to his listeners in the most natural, unpretentious, and unscripted way about what they might expect to experience. The feeling, thus, that a new spirit of animation had taken hold of this great and venerable institution prevailed at once; and the evident fact that the animating was being done by the music director himself and not just through him by some administrator, no matter how enterprising, has been of inestimable value.

In the maestro's early days here, a number of judges, including some critics, opined that it was primarily as a champion of the more out-of-the-way repertoire that he was likely to make his mark. My own judgement was different. Yes, with the Levinson premiere, and the Bernstein "Jeremiah" Symphony, and Messiaen's TurangalêÎla and L'Ascension, Eschenbach nailed his colors both boldly and brilliantly to the mast in the first month of his tenure. Yet it is perhaps the performance of Mozart's "Jupiter" Symphony at the end of that dazzling four-week stint that has remained most satisfyingly in my ears. Like the Brahms First on his opening program, and the similarly revelatory performance of the German Requiem that he led the following year, this was an object-lesson in allowing a work to develop at its natural pace, in profoundly sensitive response to the music's harmonic pulse. At the same time, as used to be the case with such great forerunners on the podium as Wilhelm Furtw‹ngler and Jascha Horenstein, this "going with the flow," far from having a disjointed effect, ended by realizing the work's architectural integrity much more convincingly than any strait-jacketed adherence to an unvarying pulse, in what is commonly thought of as the Toscanini-Szell tradition, could have done. A fundamental factor in the symphonic style, after all, is its combination, or reconciling, of variety with unity, so that the art of transition lies at the heart of both composition and conducting. Anyone‹well, almost anyone‹can give us a tune, and then go on to give us another one. What takes something like genius is to imbue each idea with its full unique character and also to lead us with inevitability from one idea to the next.

Pursuing this aim, Eschenbach has taken the path, not of safety, but as suggested above of risk‹often of unpredictability. The great classic works, just as emphatically as the best of the new ones, are inexhaustible‹they lend themselves to a multiplicity of interpretations and yield up fresh experiences at every hearing. For that reason, there is no point in a performer's tackling them if he is not prepared to take risks. In Philadelphia the maestro's risk-taking has resulted in really thrilling performances across a wide range of classical, romantic, and contemporary repertoire. Since moving from Philadelphia to the West Coast in 2005, I have had relatively few opportunities to keep up with the Orchestra's work, but a Beethoven Ninth (with a truly overwhelming finale) that I heard on a trip back to town in 2006, and a Berlioz Symphonie fantastique in Seattle during last year's U.S. tour, both served to reassure me that the standards were still as high as ever.

In the future, when the Philadelphia audience looks back over the Eschenbach era, it will surely remember a leader whose dedication to the art of music, and to the service of his public, transcends any hint of the moyen sensuel‹an idealist in the high-principled Muti mold. Christoph Eschenbach is a complete musician, and a complete human being. Equally complete has been his dedication to this orchestra and its city. It is good news that his departure from the post of music director will not mean goodbye. You are lucky to be able to look forward to return visits in the coming seasons. I shall try to take some of them in myself.

Formerly the music critic of the Chicago Daily News and visiting professor of music at Chicago Musical College of Roosevelt University, London-born Bernard Jacobson was The Philadelphia Orchestra_ã_s program annotator from 1984 to 1992, serving also as musicological adviser to Riccardo Muti. He has published three books and translations from several languages, written poetry for musical setting, and performed as narrator in recordings and in concerts around the world.