Smiles were contagious at the Barnes & Noble book store Wednesday evening as legendary singer Peter Yarrow appeared to perform some of his classic children's folk songs and to promote his latest song book, "I'm in Love with a Big Blue Frog."

Dozens of people gathered to hear the 74-year-old singer-song writer from the 1960s iconic folk trio Peter, Paul & Mary.

Yarrow did not disappoint, delighting young and old with playful, interactive renditions of "The Marvelous Toy," "Row Your Boat," "Mary Had a Little Lamb," "Leaving on a Jet Plane" and "Puff, the Magic Dragon."

The "Big Blue Frog" song was actually released by the trio in 1967. It was inspired by the civil-right movement, and reflected the protests of the day against conditions preventing blacks from exercising their freedoms. The "frog" in the song is symbolic of a black man who is dating a white woman.

"Neighbors were against their being together," said Yarrow, who suggested that "big blue frogs" today might be groups such as same-sex couples, who also may face prejudice.

"Seemingly simple children's songs, even those from hundreds of years ago, are quite profound and offer great wisdom," said Yarrow. " `Row Your Boat' features the line `life is but a dream'. That's an existential proclamation."

A long-time activist for a variety of social causes, Yarrow also spoke about the December massacre at Sandy Hook Elementary School in Newtown. "None of these children here should grow up afraid to go to school," he said. "If we want our children to be whole human beings, we need to educate their hearts, not just their intellects."

As he touched on social issues, he remembered late bandmate Mary Travers, who died in September 2009. "She used to visit this store," he said. "I still feel her spirit." Coincidentally, the song "Mary Had a Little Lamb" was the first they sang together when the trio began performing in New York's Greenwich Village.

Yarrow's fondness for and easy, guiding manner with children was apparent in his rendition of "The Marvelous Toy." Youngsters and adults alike joined in, with "sound effects" as Yarrow sang, "It went zip when it moved, pop when it stopped and whirrr when it stood still."

For his rendition of the classic, "Puff, the Magic Dragon," which Yarrow co-wrote, he gathered children around him and they all sang together.

The singer's associate and soundman Tony Arancio said "Big Blue Frog" is the latest in a series of songbooks that Yarrow has released under the trio's banner, beginning in 2007. "Puff, the Magic Dragon" was the first. Follow-ups have included "The Day is Done," "The Night Before Christmas" and "It's Raining, It's Pouring." Each song book includes a CD. The Westport stop was part of a short tour, mostly in the Northeast, to promote the latest book.

"We've had great feedback," said Arancio. "Three hundred people turned out at a Barnes & Noble in Kingston, N.Y., yesterday. You see mom and dad with the kids, grandma and grandpa, and Peter, Paul and Mary fans. A whole spectrum."

Lindsey Rossen, from Weston, said she has been a fan of Yarrow since childhood. "I love his songs, and the pictures in the books are captivating to my daughter," she said. "It's cool that he's here."