Laura Nyro, the New York-born singer and songwriter whose impassioned, iconoclastic music exploded pop song conventions in a feverish search for emotional truth, died on Tuesday at her home in Danbury, Conn. She was 49.
The cause was ovarian cancer, said Elizabeth Rush, her business representative.
Along with Joni Mitchell, Ms. Nyro (pronounced Nero) was a pioneer in the confessional, free-form school of songwriting that grew out of 1960's folk music, especially the work of Bob Dylan. A trained pianist, she had a kaleidoscopic musical sensibility that fused elements of folk, soul, gospel and Broadway tradition into intensely introspective songs that transcended easy stylistic categorization.
With her uninhibited, note-bending vocal wail, she also helped introduce the rhythm-and-blues-influenced style known as ''blue-eyed soul,'' so named because it was popularized by white singers imitating black role models. And her live concerts were fervent affairs in which the dark-haired, dark-eyed singer, exotically gowned and surrounded by roses, performed with a transported intensity.
As a recording artist, Ms. Nyro never had a gold album or a hit single, but many of her songs were hits for others. And her albums, especially her 1968 song suite ''Eli and the Thirteenth Confession'' (Columbia), a sometimes impenetrable mosaic of fragments, reflections and fantasies with a Southern gospel feel, was one of the most influential pop recordings of the late 1960's. Among the many artists inspired by Ms. Nyro's eclecticism and poetic sensibility were Rickie Lee Jones, Kate Bush, Wendy Waldman, Jane Siberry, Teena Marie, Suzanne Vega, Toni Childs, Tori Amos and Paula Cole.
Among Ms. Nyro's biggest hits for others were the songs ''And When I Die'' (recorded by Peter, Paul and Mary and Blood, Sweat and Tears), ''Wedding Bell Blues'' (the Fifth Dimension), ''Sweet Blindness'' (the Fifth Dimension), ''Stoned Soul Picnic'' (the Fifth Dimension), ''Eli's Coming'' (Three Dog Night) and ''Stoney End'' (Barbra Streisand).
Ms. Nyro was born Laura Nigro in the Bronx on Oct. 18, 1947. Her father was a jazz trumpeter who practiced for hours at home. An undisciplined child prodigy, Ms. Nyro began writing songs at age 8 and later attended the High School of Music and Art in Manhattan. As a teen-ager she experimented with psychedelic drugs, absorbed musical influences as far-ranging as Bob Dylan, John Coltrane and Debussy, and at 18 made her first extended club appearance at the Hungry i coffeehouse in San Francisco.
In 1966, Verve/Folkways released her debut album, ''More Than a New Discovery,'' a remarkably sophisticated collection of original songs that Columbia later purchased and reissued in 1973 as ''The First Songs.'' Widely admired, it led to an invitation to perform at the 1967 Monterey Pop Festival, where her introspective music proved so out of place amid the high-powered rock of Jimi Hendrix and Janis Joplin that she was shouted off the stage.
Within the year, however, several of Ms. Nyro's songs had become hits for others, and she was signed by Columbia. In March 1968, the label released ''Eli and the Thirteenth Confession,'' her autobiographical album about a young woman's spiritual journey from childhood to maturity. With its abrupt changes of tempo and style and its fiercely emotional singing, the record was unlike anything that had been heard in pop music, and it laid the groundwork for a female-dominated genre of quirky, reflective songwriting that continues to this day.
On her next two albums, ''New York Tendaberry'' (1969) and ''Christmas and the Beads of Sweat'' (1970), Ms. Nyro retreated somewhat from the boundary-breaking experimentalism of ''Eli'' and settled into her characteristic style, which remained eclectic but had its strongest roots in the Philadelphia pop-soul sound of songwriters like Thom Bell, Kenneth Gamble and Leon Huff, and Todd Rundgren. Her 1971 album, ''Gonna Take a Miracle,'' a collaboration with the rhythm-and-blues group LaBelle, was a tribute to New York street music of an earlier era that featured jubilant remakes of old doo-wop and Motown favorites.
Never comfortable in the limelight, Ms. Nyro married and retreated from the music business to lead a secluded life for the next three years in a fishing village in Massachusetts. After the marriage ended in divorce, she returned to recording, putting out ''Smile'' (1976), her first album in four years. Here, and in her later Columbia albums, ''Nested'' (1978), ''Mother's Spiritual'' (1984) and ''Walk the Dog and Light the Light'' (1993), her songs gave increasingly direct expression to the pantheism that had always lurked in her writing. But if her later songs exalted pacifism, feminism, motherhood and animal rights, the emotional turmoil of old was never far from the surface.
Ms. Nyro personally selected all 34 of the songs on a recently released two-disk retrospective of her work, ''The Best of Laura Nyro: Stoned Soul Picnic'' (Columbia/Legacy).
She is survived by a son, Gil Bianchini, and her companion, Maria Desiderio.
Photo: The singer and songwriter Laura Nyro in the late 1970's.
