Arthur Russell — former Midwesterner, avant-gardist in the making — moved to New York from San Francisco in the early 1970s to study at the Manhattan School of Music, where his teachers included the composer Charles Wuorinen. It wasn’t a happy relationship.Call it a clash of uptown and downtown, when such a dichotomy existed: Wuorinen, a prickly modernist of the academy, versus Russell, a post-Cagean thinker from Allen Ginsberg’s circle who was into Indian classical music. Neither was likely to be a fan of the other, and things came to a head over Russell’s “City Park,” created and first performed in 1973.The piece blends texts from Ezra Pound and Gertrude Stein with a nonlinear, modular score of repetitive phrases and Fluxus-inspired directions. Russell is said to have explained to Wuorinen that the structure allows listeners to “plug out and then plug back in again without losing anything essential.”Wuorinen, famously cranky, shot back, “That’s the most unattractive thing I’ve ever heard.”Russell quickly drifted away from Wuorinen, seeking guidance from a different composer, Christian Wolff, and getting more into electronics. His career developed, ever-changing and exploratory — gathering support from peers like Philip Glass and David Byrne, freely floating among the worlds of classical music, disco and songwriting — and “City Park” faded into distant memory. Russell died in 1992 at 40, a victim of the AIDS epidemic, and the piece lived on mostly as an amusing anecdote about a lost work.Nick Hallett, center, rehearsing “City Park” at Wesleyan University, with Parsa Ferdowsi, left, and Lea Bertucci.Adrian Martinez Chavez for The New York TimesNow, though, it has been reconstructed and will be performed for the first time in five decades at the New York City AIDS Memorial on Saturday, presented by the memorial outdoors for free and featuring an ensemble that includes Russell’s close collaborators. The musician Nick Hallett, who is responsible for the reconstruction, said that the piece was “about New York City,” and more important, “tells the story of Arthur’s New York City.”Russell is a particular case among composers lost to AIDS. Most around his age died without publishers or estates; their music languishes in archives like those at the New York Public Library. Russell may have been poor and perpetually underground, despite high-profile friends and collaborators like Talking Heads, but at least he had the infrastructure of an estate to maintain his legacy.More of a problem was his output. Russell, who was often seen around town with his Walkman, obsessing over mixing and production, recorded prolifically but released little. His attitude inspired some: David Van Tieghem, the composer and percussionist, who met Russell at the Manhattan School of Music and performed in the premiere of “City Park,” respected his friend’s belief that “if you’re going to do it, do it as best you can.”“City Park” features prerecorded material, scratch loops and instructions for a turntablist.Adrian Martinez Chavez for The New York TimesRussell’s piece has been prepared at Wesleyan ahead of its performance in New York on Saturday.Adrian Martinez Chavez for The New York TimesAnother collaborator, though, the trombonist Peter Zummo, said Russell could be obstinate about not making more of a living off his art. “One time he came to me, and he said, ‘The ideal record would be one,’ a press of one,” Zummo recalled. “Which would make it a work of art. He had standards, but there was also a stubbornness.”Russell has long been known for bits of his catalog, including the album “24→24 Music” (for which he enlisted friends like Zummo, Julius Eastman and Peter Gordon) and the disco song “Is It All Over My Face.” But his music, with its wide stylistic range, has taken on new life in the decades after his death as the recordings he left behind have been released this century.“I love seeing how people really latch onto it,” Van Tieghem said. “I have students at the New School who are huge fans. People have only recently come across his stuff and just love it.”Among Russell’s longtime admirers is Hallett, 49, who came of age in clubs and looked to him as an artist who “bridged the gap between disco, experimental and songs.” Hallett eventually met people from Russell’s circle, including Van Tieghem and Zummo, as well as younger musicians who were interested in preserving Russell’s legacy.Over the years, “City Park” lingered in Hallett’s mind like “a faint question mark,” he said. “Every new description of it intrigued me in a new way.” So, when the opportunity arose to reconstruct and revive the piece, he seized it.“City Park” includes Fluxus-inspired instructions for players, including “Play like the clouds always.”Adrian Martinez Chavez for The New York TimesHallett started with several sheets of material — which was all that Russell’s estate was aware had survived. There were two pages of notes, and two more of instructions on manuscript paper. Those only introduced more questions. “I saw so many potential roads to travel down,” Hallett said. “We see references to ‘scratch pulse.’ We see instructions for a turntablist. We see instructions for electronic tape.”He next turned to archivists at the New York Public Library, who tracked down two recordings. When Hallett listened to them, he was surprised. “From the score instructions, I anticipated a disco masterpiece,” he said. “This was different. And it fascinated me.”Unable to hear the turntable, he sought help from those who had performed in the premiere to figure out why. No one seemed to remember anything of use until, after what Hallett called some “memory jogging,” it emerged that the D.J. score is meant to be inaudible to everyone but the drummer.“Arthur uses the turntable not as we’d imagine a hip-hop D.J., but more in the way that John Cage was using the turntable in 1939, in the first ‘Imaginary Landscape,’” Hallett said. “The D.J. is the inaudible brain of the work; the drummer responds only to the scratch loops.”Not only is the influence of Cage here, but also that of artists he knew intimately, including Ginsberg and Jackson Mac Low. Among notated instructions are Fluxus-esque ones: “Play like the clouds always” and “Give a signal to someone, another player, without explaining what it’s for.” Elsewhere, musicians are told, “ask the drummer (when he’s not playing) what section he’s in, and play something from that section.”The New York City AIDS Memorial, where “City Park” will be performed outdoors for free on Saturday.Sara Krulwich/The New York Times“The score is a map,” Hallett said, “one that is not intended to be followed literally but one that puts agency in the performer and allows them to make choices.”Van Tieghem said that, as far as he could remember, there wasn’t any rehearsal before “City Park” premiered. There is, Hallett said, a “great amount of planning” that goes into this piece, but it can’t be prepared in a traditional way. Saturday’s players got together at Wesleyan University last week, but, accustomed to Russell’s idiom and performance practice, are not repeatedly running through it.“You shouldn’t over-rehearse a piece like this,” Hallett said. “It’s meant to be interpreted in the moment.”That doesn’t mean it’s easy, though. Zummo said that, like Terry Riley’s classic “In C,” “City Park” can’t be picked up by any musician. Looking at the score recently, he was reminded of the questions he used to ask Russell before playing a new piece of his.“I would say something like, ‘Where do you want me to start?’ and he said, ‘Anywhere,’” Zummo recalled. “At one point I asked a similar question, and he said, ‘It’s a sound field.’ It’s another way to describe the open form, I guess, and ‘City Park’ brings that to mind. In a way, it’s not going anywhere.” More