Eduardo Falu on composing: “There is nothing more beautiful and difficult. I wander and wander with the guitar until that moment I am waiting for arrives. One has to be ready to grasp inspiration from the air because it is very elusive and can slip away so easily.” (Clarin)

Eduardo Falú, an Argentine guitarist and composer who married the rigor and harmony of folk music with the virtuosity of classical technique and who became a leading cultural ambassador, died Aug. 9 in Cordoba province. He was 90.

The death, of undisclosed causes, was announced by the Argentine Society of Authors and Music Composers.

Mr. Falú, who sang with a warm, vibrant baritone, was widely regarded as a master of Argentine folk music, in particular the peppery chacareras and romantic zambas from the northwestern part of the country where he grew up. He also studied harmony and music theory and said it was his life’s work to “give another dimension to folklore” by bridging indigenous and classic sounds.

Starting in the late 1950s, he appeared on stages from Paris to Washington to Tokyo. Reviewing one of his performances, a San Francisco Chronicle music critic noted Mr. Falú’s “curious mix of savage abandon and studied refinement.”

He was associated with the “nueva cancion” (new song) movement of the 1960s and 1970s, which knitted folk elements with protest lyrics about social injustice. His outlook was not as overtly political as Mercedes Sosa’s, who became an international cause celebre after she was harassed by the military junta that ruled the country from 1976 to 1983.

“He was more a traditional folklorist who wrote gorgeous music,” said ethnomusicologist Jonathan Ritter of the University of California at Riverside. “He transcends time and ideology — with songs about love and lost love and nostalgia.”

In a career spanning more than six decades, Mr. Falú wrote hundreds of compositions that often drew on Latin American poetry and literature. He set to music poems by Jorge Luis Borges (“Hombre de Antigua Fe”), Manuel Castilla (“La Atardecida”) and Jaime Dávalos (“Zamba de la Candelaria”).

More ambitious projects included a 1971 collaboration with the Argentine novelist Ernesto Sabato, “Romance de la Muerte de Juan Lavalle,” about the 19th-century Argentine military and political leader who was killed in battle and whose followers absconded with his remains to Bolivia to prevent desecration.

“My job was never at the service of any political line,” Mr. Falú told the Spanish newspaper El País in 1980. “I think that everything that happens is temporary and there are crises. But in all man’s attitude, there are always going to be values that are perennial and eternal, values that have to do with destiny, with love, with loyalty. These are the values that inspire art.”

Eduardo Yamil Falú was born on July 7, 1923, in El Galpon, in Argentina’s northern Salta province. His parents, Syrian immigrants, owned a general store frequented by farmers and traders. He was smitten at an early age by the region’s indigenous music, once calling it “something lively, dynamic and evolutionary.”

He said that he was 11 when learned guitar from a local barber, who “played guitar when he had no victims in the chair.”

He spent his teenage years in the city of Salta, where he studied to become a teacher. He told the Argentine Web site that his father was against a career in music, calling it a “passport to partying and laziness.” He turned professional anyway, working with contemporaries such as poet César Perdiguero to compose songs about the human condition, such as this 1942 verse about a field worker:

As bitter as tobacco

is my whole life long

But I sweeten it, boss, with

the sugar of song.

Intrigued, a programmer at a Buenos Aires radio station invited Mr. Falú on the air in 1945, a time when tango and bolero dominated the airwaves. Over the next decade, Mr. Falú was among a handful of artists, most prominently singer-guitarist Atahualpa Yupanqui, who began to build more mainstream audiences for folklore music through records, radio appearances and concerts.

Mr. Falú made his recording debut with “La Vidala del Nombrador,” in 1950. By the end of the decade, he was in demand as a performer in France, the Soviet Union and especially Japan, where he played more than 200 dates.

He and his wife, Aida Nefer Fidelibus, had two children, one of whom, Juan José, became a classical guitarist and composer who sometimes performed with his father.

The elder Falú continued to write music and record through recent years, including duets with esteemed flamenco guitarist Paco Peña.

“Composing . . . there is nothing more beautiful and difficult,” Mr. Falú told Americas magazine in 1989. “I wander and wander with the guitar until that moment I am waiting for arrives. One has to be ready to grasp inspiration from the air because it is very elusive and can slip away so easily.”