Peter, Paul and Mary Saga : Music: After 30 years, the trio, who perform in San Diego Monday, are still going strong with music that has a message.

“We met in New York City in late 1960, then we rehearsed for seven months, and then we performed at the Bitter End.” With that oversimplification, Peter Yarrow, speaking by phone from his hotel room north of Los Angeles earlier this week, described how he, Noel Paul Stookey and Mary Travers became the legendary folk trio, Peter, Paul and Mary.

This year, the threesome is celebrating 30 years together with a full slate of commitments. One of these is a tour that brings them to town Monday night for a concert at the Embarcadero Marina Park South--the outdoor facility on the bay side of the San Diego Convention Center that is home to the San Diego Symphony’s SummerPops series. (Monday’s concert is part of the Pops’ “EXTRA!” series; the symphony will not perform.)

What came after the trio’s auspicious debut is, of course, a matter of public record. Throughout the early ‘60s, the group scored hits with recordings of

“Lemon Tree,” “If I Had a Hammer,” “Puff, the Magic Dragon” and two songs by a then-unknown Bob Dylan: “Blowin’ in the Wind” and “Don’t Think Twice, It’s Alright.” They also set a precedent by being the first phenomenally popular musical act of the era to espouse civil-rights and anti-war activism.

In 1967, Peter, Paul and Mary shifted gears with the inventively produced “I Dig Rock and Roll Music,” then returned to pristine folk form in 1969 with a No. 1 rendition of “Leavin’ on a Jet Plane,” a ballad by another unknown, John Denver. A year later, they disbanded to pursue solo careers.

Stookey soon had success with “The Wedding Song (There is Love),” which he wrote for Yarrow’s nuptials, and Yarrow wrote and co-produced Mary MacGregor’s 1977 hit, “Torn Between Two Lovers.” Travers released five solo albums, hosted a radio talk show and starred in her own BBC television series.

The trio reunited in 1972 for a George McGovern campaign fund-raiser, and again six years later for an anti-nuclear benefit at the Hollywood Bowl. Since then, they’ve intermittently recorded as Peter, Paul and Mary, and they continue to perform about 60 concerts a year as an ensemble.

For the most part, the trio’s anniversary is a joyous observance of three decades of music making. But the celebratory spotlight also reveals that--both collectively and individually--they maintain a balance between art and advocacy. All three remain involved in such social causes as homelessness, the environment, world hunger, apartheid, the sanctuary movement and other issues that affect the human condition.

Monday’s concert, in fact, is a benefit for the Wellness Community, an organization that helps people redefine their lives in order to emotionally and psychologically gain the upper hand in the fight with terminal disease. For Yarrow, especially, that tie-in proffers a double dose of poignancy.

In 1988, the New York-based Yarrow wrote a song, “With Your Face to the Wind (Harriet’s Song),” at the request of a San Diegan whose mother, Harriet Nestor, an ovarian cancer patient, was establishing the San Diego chapter of the Wellness Community. Yarrow sent a cassette of the song to Nestor--who played it at the opening of the organization’s Kearny Mesa chapter--and he telephoned her on a couple of occasions thereafter. He considered the song-gift a private matter.

But one day, Yarrow played the song for his then-86-year-old mother, who began crying. “This song isn’t just for Harriet,” she said. “This song is for all of us. You must sing this song for other people.”

Soon, Peter, Paul and Mary were performing “With Your Face to the Wind” in their concerts, including a September, 1989, show at the Universal Amphitheatre in Los Angeles that was attended by Burton Nestor and his three sons. (Harriet had died several months earlier.) The song was included on the trio’s 1990 album, “Flowers and Stones.”

When the subject was raised in the interview, Yarrow grew wistful at the recollection of the circumstances surrounding that song, which recently assumed a new perspective.

“This is a somewhat difficult time for me,” he said softly. “My mother passed away on June 28. I am very lucky in that I was able to spend a great deal of time with her toward the end; I was at the Connecticut Hospice almost around-the-clock. She was almost beatific in her final days, and the whole experience was profoundly moving. But now, you know, I’m left with the simple case of missing her.”

In the typical music interview, such unabashed emotion might have posed an uncomfortble hurdle. But, because Peter, Paul and Mary’s music has always been humanistically directed and life- affirming, it seemed fitting that the musician’s personal experiences should be woven into the tapestry of the trio’s professional life.

“Life goes on,” Yarrow said, “but something like this certainly adds some weight to other concerns one faces while touring and working on various projects.”

One of those projects is a children’s television special slated for spring of 1992. Yarrow has expertise in that department; several years ago, his three children’s specials for the CBS network--based on “Puff, the Magic Dragon”--earned him an Emmy nomination.

“Because of our outside interests, we’ve never been just a trio singing songs,” Yarrow said. “And, even when we are musically engaged, we do it from a certain perspective. There’s a legacy of great music that we inherited, songs that excited us. One way we’re celebrating our 30th anniversary is by sharing that folk legacy with children, in the form of a PBS special. The working title is ‘Peter, Paul and Mommy,’ which is what we called our first (1969) children’s album.”

Some of the songs from that special, which will be released on an album, will be included in Monday’s concert. The bayside show will also feature a short solo segment by Travers that’s bound to resonate fitfully among the Navy warships docked near the concert site.

“Being Peter, Paul and Mary, we couldn’t possibly go without commenting on the recent war,” Yarrow said. “Mary does a segment in which she combines the songs ‘Johnny, I Hardly Knew Ye’ with ‘When Johnny Comes Marching Home.’ I think it’s a lovely and necessary commentary.”

Yarrow’s own words on the subject are more pointed. “It’s obscene to rejoice in military victory,” he said. “It’s an anachronism at this time, and a dangerous precedent, historically, for people to feel a sense of national pride based on military might. And considering that the President said we have no quarrel with the Iraqi people, it’s unconscionable not to even acknowledge the suffering we’ve caused, or the 100,000-plus people who have died.

“We’re acting like a high school football team after a big win, instead of like participants in a great tragedy,” Yarrow said. “We can be prayerfully grateful that relatively few of our American brothers and sisters died. But what has happened to our sensibility? It’s certainly possible that war with Hussein was an ultimate destiny, but because of our rush to war we’ll never know, will we?”

Yarrow allowed that, so far, the group has encountered little resistance to their anti-war gesture.

“Probably, most of the people who come to our concerts have at least a generic opposition to war,” he said. “And, besides, Mary’s piece is a small segment in a show that features a lot of other music of the sort that fans have come to expect from us. I’m not anticipating anything other than a warm, unifying, fun evening.”

Peter, Paul and Mary perform at 7:30 at the Embarcadero Marina Park South--the outdoor facility on the bayside of the San Diego Convention Center that is home to the San Diego Symphony’s SummerPops series. The concert is part of the Pops’ “EXTRA!” series; the symphony will not perform. Tickets, which range in price from $10 to $25, can be purchased at the Marina Park South ticket office (8th Avenue and Harbor Drive); at the Copley Symphony Hall ticket office (750 B Street); at all TicketMaster outlets, or by calling 278-TIXS.