James Tenney, who died Thursday at 72, was by common acclamation the most renowned obscure composer in America.

He was held in high esteem by critics and by composers including John Cage and Steve Reich. He was a student of Cage, as well as Edgard Varèse and Harry Partch, his professor at the University of Illinois who also employed him and then fired him for insubordination.

Tenney was compared to Zelig for being present at so much of the history of 20th-century music.

“In a way he stands at the center of American music, a kind of focal point,” Kyle Gann wrote in “American Music in the Twentieth Century” (1997). “No other composer is so revered by fellow composers, and so unknown to the public at large.”

Tenney grew up in Arizona and Colorado and said his life was transformed when, as a 16-year-old piano student, he went to hear Cage play “Sonatas and Interludes,” the landmark piece for prepared piano.

As a piano student in the 1950s at Juilliard, where his roommate was the filmmaker Stan Brakhage, Tenney became friendly with Cage and over a beer asked the composer for permission to record parts of “Sonatas and Interludes” for a film Brakhage was making.

“He said, ‘I’m not interested in that music anymore, you can do what you want with it,'” Tenney told the Los Angeles Times in 2002.

In 2002, a half-century after the Denver performance that “blew me away,” Tenney painstakingly re-created the performance at the California Institute of the Arts, following Cage’s instructions down to the size of the screws, washers, and plastic strips jammed between the piano strings to produce the piece’s unsettling tones.

Over the years, the admiration had become mutual; when Mr. Gann asked Cage in 1989 whom he would study with if he were a young man, Cage replied, “James Tenney.”

Tenney dropped out of Juilliard, somehow ended up graduating from Bennington — then a women’s school — and moved to Urbana-Champaign to enroll in one of the first ever electronic music classes.

He eventually was hired as a researcher in psychoacoustics by Bell Telephone Labs; it was there that Tenney produced some of the first programmed electronic music. Yet he was also among the first to abandon the technique, in the early 1970s. “I’m not a knob-twirler,” he once said. Also at Bell Labs, Tenney pioneered the art of sampling, with a composition made by chopping up and reassembling Elvis Presley’s version of “Blue Suede Shoes.”

While living in New York in the 1960s, Tenney taught at the Polytechnic Institute of Brooklyn and was associated with the Fluxus artists Nam June Paik, Charlotte Moorman, and Tenney’s first wife, Carolee Schneeman. He conducted an ensemble called the Tone Roads Chamber Ensemble and performed with Philip Glass and Mr. Reich.

He taught at CalArts from the early 1970s and also had appointments at the University of California at Santa Cruz, and at York University in Toronto, where he was named distinguished research professor in 1994. At his death, he was back at CalArts, where he held the Roy E. Disney Family Chair in Musical Composition.

Tenney’s body of work has a stunning breadth: electronic programmed pieces, minimalism, 12-tone, and even ragtime. He was most prolific as a composer of chamber music, but there were also orchestral works, including several for “variable orchestra” — which specified a minimum number of players, usually 12 or 16. Many of his works use alternate tuning systems (a la Partch) and many, if not most, bear dedications, often to other composers.

Tenney wrote two books, “META + HODOS: A Phenomenology of 20th-Century Musical Materials and an Approach to the Study of Form” (1961) and “A History of ‘Consonance’ and ‘Dissonance'” (1988).

In 2005, Tenney performed Cage’s “Sonatas and Interludes” at the Museum of Modern Art in New York, as accompaniment to a Brakhage film. The pianist Jenny Lin, who performed one of Tenney’s works for prepared piano at the same event, wrote in a recent remembrance, “He mended the differences between musical worlds and bridged the gaps between extremes.”

James Tenney

Born in 1934, in Silver City, N.M.; died August 24 of lung cancer in Valencia, Calif.; he was married four times, lastly to Lauren Pratt, who survives him, as do his children, Nathan Tenney, Justin Tenney, Adrian Tenney, and Mielle Turner, and three grandchildren.