Mary Travers

Having formed in 1961, Peter, Paul and Mary's achievement was to bring folk music out of the socks-and-sandals division into the commercial mainstream. The two guitarists in the band, Peter Yarrow and Noel "Paul" Stookey, may have appeared unremarkable in their beatnik-style beards; the blonde and willowy Mary Travers, on the other hand, invested the group with a kind of Nordic glamour. Their manager, Albert B Grossman (who was also to handle Bob Dylan), was adamant that she should retain an aura of mystery about her, and insisted that she never spoke on stage.

Peter, Paul and Mary's three-part harmonies generated 13 Top 40 hits (six in the Top 10), and eight gold albums and five platinum. Unsurprisingly, the group was at times criticised by purists as "too commercial".

Mary Travers denied the charge, insisting: "I think there are many qualities that allow a song to transcend its own time, whether it's a love song, a lullaby, or a song of protest. They all have to have a certain elegance to them, and simplicity and authenticity. They can't sound as if they were only appealing to a narrow group of people... The thing about really great songs is that they're everybody's music."

As was de rigueur with folk groups in the 1960s, Peter, Paul and Mary opposed the war in Vietnam and embraced the great liberal causes of the day. In 1963 their recording of Blowin' in the Wind became a Top 10 hit and was taken up by the civil rights movement.

In August that year Dr Martin Luther King delivered his "I Have a Dream" speech during the March on Washington; Peter, Paul and Mary were there too, entertaining the crowds at the Lincoln Memorial alongside Dylan, Joan Baez and other artists who embraced the protest movement.

Mary Allin Travers was born on November 9 1936 at Louisville, Kentucky. Both her parents were journalists, and when she was two the family moved to New York City, where Mary attended Elisabeth Irwin High School.

Her home turf was the bohemian district of Greenwich Village, and she haunted the coffee house circuit listening to the folk musicians who performed there. She was developing a powerful voice of her own, and sang at the Sunday afternoon folk music gatherings in Washington Square Park, then recorded with a group of teenagers called The Song Swappers, who released two albums and twice provided backing for Pete Seeger in concerts at Carnegie Hall. In 1958 she appeared in The Next President, a Broadway show starring the comedian Mort Sahl.

It is doubtful, however, that Mary Travers – who suffered from a crippling shyness – would ever have had a professional singing career had it not been for Albert B Grossman. In 1961 he was managing an unknown folk performer called Peter Yarrow, and was looking for a girl and another man to form a trio which he could turn into an updated version of The Weavers.

Noel Stookey (who became "Paul" for alliterative purposes) and Mary Travers were selected to join Yarrow, and the new group rehearsed for seven months at Mary's Greenwich Village apartment before making their debut at The Bitter End coffee house.

Their debut album came out in 1962, remaining in the Top Ten for 10 months and the Top 20 for two years, and they immediately had hits with their versions of If I Had a Hammer and Lemon Tree. The former won Grammys for best folk recording and best performance by a vocal group.

Their second album, Moving, included Puff (The Magic Dragon), which reached No 2 in the charts. Despite its title, it was not about smoking dope but derives from a poem by Lenny Lipton about the lost innocence of childhood. They brought Bob Dylan to a massive audience in 1963 with their third album, In the Wind, which featured three of his songs – Don't Think Twice, It's Alright and Blowin' in the Wind.

When fashions changed, and Dylan went electric, the writing was on the wall for groups such as Peter, Paul and Mary. But they soldiered on, releasing the single I Dig Rock and Roll Music in 1967 and John Denver's Leaving on a Jet Plane two years later. They also recorded songs by Gordon Lightfoot and Laura Nyro.

The trio remained successful for the rest of the decade – the last of their five Grammys came in 1969, for their Peter, Paul and Mommy, honoured as best children's album – but split up in 1971 to pursue careers as solo artists.

Mary Travers went on to release five albums, but none had the success she enjoyed as part of the group. She also hosted a syndicated radio show, lectured at colleges on "Society and its Effect on Music" and wrote for newspapers.

She continued her work as a political activist, taking part in missions to El Salvador and Nicaragua, and, in 1983, visiting the Soviet Union to investigate the problems faced by Russian Jews. With Peter and Paul she performed at national marches for "women's choice" in Washington and demonstrated in support of the anti-apartheid movement outside the South African embassy. The trio also campaigned against homelessness in New York City and in support of migrant strawberry workers in California.

Over the years there were a number of reunion tours, and nearly 20 new albums between 1978 and 2008, including a 35th anniversary release, Lifelines, with Ramblin' Jack Elliott, Dave Van Ronk and Pete Seeger. A boxed set of their music was released in 2004.

In recent years Mary Travers had been suffering from leukemia, and performed a last reunion concert, at New Brunswick, New Jersey, in May this year.

Mary Travers's first three marriages ended in divorce. She is survived by her fourth husband, Ethan Robbins, and two daughters.