NEW YORK, NY.- In November 1998, French composer Gérard Grisey went out to dinner with friends in Milan. He could be anxious, but he seemed strangely grounded that evening.

Atli Ingolfsson — a former student and friend, who was among those I interviewed for my new book, “The Life and Music of Gérard Grisey: Delirium and Form” — noticed that the composer didn’t complain about the food, as he sometimes did, nor did the cigar smoke from the next table bother him, as it often would.

“I feel good,” said Grisey, a pioneer of spectral music, which is inspired by acoustics. “Maybe I won’t compose anymore.”

He was unusually satisfied with his latest composition, “Quatre Chants pour Franchir le Seuil,” or “Four Songs for Crossing the Threshold,” a 40-minute work for solo soprano and an ensemble of 15 players. Grisey intended the piece as a requiem for his mother, Lucie Monna, who had died in 1995. He completed it in the summer of 1998 while alone in a village in the Swiss Alps. “After three months in Schlans in the utmost silence and concentration,” he wrote in his journal, “I finished ‘Quatre chants’ with the lullaby of the dawn.”

Born in 1946 to Monna and Jules Henri Grisey, a farm boy turned Resistance operative and car mechanic, Grisey became an essential figure in contemporary classical music. He was raised in the provincial eastern town of Belfort. At 5, he began playing the humble accordion. Then, at 9, he wrote his first piece, and progressed quickly, studying composition at the Paris Conservatory with Olivier Messiaen.

In 1974, Grisey completed arguably the first piece of spectral music — “Dérives,” for large orchestra — while on a scholarship at the Villa Medici in Rome. In that piece and the more famous works that followed, including six later collated into the orchestra cycle “Les Espaces Acoustiques” (1974-85), he used the harmonic spectrum, noise and linear musical processes as building blocks. Unlike many of the serial composers prominent at the time, Grisey wanted to foreground the capacities of human listening. The contours of his pieces are often easily audible.

“We are musicians, and our model is sound not literature,” Grisey said at a lecture in 1982, “sound not mathematics, sound not theater, plastic arts, quantum theory, geology, astrology or acupuncture.”

“Four Songs” signified the beginning of a new period in Grisey’s output. By the mid-’90s, his first spectral pieces had spawned imitators and he had grown wary of repeating himself. Four meticulously chosen texts helped him discover a freer way of working. In the first movement, which sets a poem by Christian Gabriel le Guez Ricord, an angel is pulled down from heaven by lamenting saxophones and metallic percussion. In the second, the soprano recites an archaeologist’s survey of the writing on ancient Egyptian sarcophagi — complete with indications of illegible hieroglyphics and destroyed coffins — accompanied by a slowly mutating harp motive.

In the third movement, which uses a fragment by the ancient Greek poet Erinna, the soprano is overwhelmed by the echoes of her own voice. And in the final two movements, the singer, inhabiting the character of Gilgamesh, describes the myth’s apocalyptic flood and its aftermath.

Grisey illustrates his texts as a Romantic lieder composer might: In the fourth movement, pattering rainfall turns into a violent storm, and microtonal tubas evoke the groans of dying elephants. But the work has no traditional ending. In the fifth and final piece, not a complete song but a short “Lullaby,” a crystalline, pulsing texture is there one second and gone the next.

On the early morning of Nov. 10, 1998, Grisey returned from Milan to the Paris apartment he shared with his partner, mezzo-soprano Mireille Deguy. The “Four Songs” were originally meant for her to sing, but during the composition process Grisey decided he needed high notes beyond her range.

“Don’t worry,” she told him. “You’ll write another piece for me.”

After breakfast, Deguy went to work. Grisey left for a meeting at the Paris Conservatory, where he was a professor. He came home at lunchtime and made an unusual number of calls to friends. Deguy returned to their apartment in the evening. They had plans to meet friends for dinner, but Grisey suggested having a drink before leaving, wanting to savor their early-evening contentment.

Deguy remembers that Grisey removed his watch and asked her to do the same before he collapsed from a brain aneurysm. He fell into a coma and was brought to a hospital. He crossed the threshold the following morning, at dawn. He was 52 years old.

Intended as a requiem, “Four Songs” became an autorequiem. It’s an unsettling circumstance, made more so by the frequent references to death in Grisey’s writings. “He was fascinated by death, as a symbol and as a fact,” said Gérard Zinsstag, a composer and close friend. In June 1998, after finishing the “Four Songs,” Grisey had written in his diary: “Why are the final decisions the most painful ones? Saying goodbye? Attachment? To what, from what?”

Such eerie consonances have a history in classical music. Mozart left his Requiem unfinished when he died in 1791. In 1983, composer Claude Vivier, a friend of Grisey’s, was murdered, leaving behind the beginning of a piece called “Do You Believe in the Immortality of the Soul?”

Did these composers know — consciously or subconsciously — what was coming?

In Grisey’s case, the evidence suggests that he did not. After completing the “Four Songs,” he began sketching a piece based on lines from Samuel Beckett’s French-language poetry collection “Mirlitonnades.” Grisey hadn’t settled on an instrumentation before he died, but he did plan to use a mezzo-soprano voice in Deguy’s range. The couple had spoken about leaving Paris for the country and adopting a child.

Many of Grisey’s friends recalled that after completing the “Four Songs,” he was exhilarated about the new aesthetic possibilities he had discovered. He told a friend, astrophysicist Jean-Pierre Luminet, that he’d found “a new language that begins with this composition.” A letter to Armin Köhler, then the artistic director of the Donaueschingen Music Festival in Germany, shows that Grisey was planning commissions past the year 2000.

Rather than a premonition, “Four Songs” is the remainder of a tragedy: the first piece in a late style that would never come. Grisey’s life ended as the “Lullaby” of the “Four Songs” does. One moment, he was there; the next, he was gone.

In February 1999, the “Four Songs” premiered at Queen Elizabeth Hall in London, performed by the London Sinfonietta and soprano Valdine Anderson under the direction of George Benjamin. A group of those close to Grisey traveled from Paris to London for the concert. “That a man in the prime of life feels an imperative to write his own elegy without realizing it,” Fiona Maddocks wrote in The Guardian, “raised questions yet more disturbing than the potent work itself.”

The effect of the music must have been staggering: After more than two decades, most of Grisey’s circle still finds the performance impossible to talk about.

This article originally appeared in The New York Times.