Nonesuch Records releases Tell My Sister, a special three-disc set comprising remastered versions of Kate & Anna McGarrigle's beloved 1976 self-titled debut; its equally praised 1977 follow-up, Dancer with Bruised Knees; and a collection of previously unreleased songs, including solo and duo demos, on May 3, 2011. Joe Boyd, who produced the McGarrigles’ first two albums, assembled the material for the third disc in addition to serving as producer for the whole set.

The release coincides with a two-night tribute to Kate McGarrigle—who died of sarcoma last year—May 12 and 13 at New York City’s Town Hall. Curated by Joe Boyd, the concerts will feature performances by Kate’s children, Martha and Rufus Wainwright, and her sister Anna, as well as Emmylou Harris, Antony Hegarty, Norah Jones, and Teddy Thompson, among others. Profits from the concerts will go toward creating the Kate McGarrigle Sarcoma Research Fund.

Raised in an artistic family in St. Sauveur, Quebec, Kate moved to New York in 1969 to pursue a singing career while Anna studied art in Montreal. Both wrote many songs during this period, including Anna’s “Heart Like a Wheel,” which eventually appeared on their debut album (and was made famous by Linda Ronstadt in 1974), and Kate’s “The Work Song,” which Maria Muldaur recorded in 1973. It was another Muldaur recording of a McGarrigle song that first brought the sisters to the attention of then–Warner Bros. Records President Lenny Waronker.

“Lenny and I loved ‘Cool River’ for Maria Muldaur’s second album. The tape came from Kate McGarrigle, so we assumed it was her song and her voice layering up those delicious harmonies,” recalls Joe Boyd. “The song turned out to be Anna’s; and those harmonies weren’t overdubbed, they were live, the sisters’ overtones vibrating in the air around the microphone, making two voices sound like a multitude. Warners gave them a contract; Greg [Prestopino] and I co-produced with my old pal John Wood (Nick Drake, etc.) engineering.”

Among many other critical accolades, Melody Maker named Kate & Anna McGarrigle Album of the Year and the New York Times named it to its 10 Favorite Disks list, saying “This folkish debut disk was the most charming, purely beautiful and sentimentally moving record of 1976.” The album’s 12 tracks were mostly written by the sisters, with the few exceptions including a track by Kate’s then-husband Loudon Wainwright III. Although the album did not achieve commercial success upon its release, it has come to be seen as a classic over the ensuing years.

The dozen tracks on Dancer with Bruised Knees, released the following year, are mainly by the McGarrigles, as well, with two traditional French songs. Longtime Village Voice critic Robert Christgau gave it an A, calling it “even better than the debut.” Boyd, who produced the record, says, “Its only problem was the album it had to follow.”

In approaching Tell My Sister’s third disc of previously unreleased material, Boyd says, “I was wary of listening to the demos, afraid they might expose our production as overdone compared to the wonder of the two sisters sitting side by side at the piano, harmonizing like goddesses. But plain and fancy both sound great to me 37 years on.”

Anna McGarrigle said of those first recordings: “Kate could easily have had a solo career, as is evident from her early song demos, but she told me, ‘I don’t want to do this by myself.’ So I put my puppet-making career on hold. To paraphrase her ‘Blues in D,’ I couldn’t let the poor girl down. Thank you for asking me, little sister.”