Martha Wainwright: All I Want

Joni came along when few women wrote their own songs. They were marginalised and surrounded by men, but she was never defined by that. Her songs are her own story - and she just happens to be a woman. All I Want is incredibly hard to sing because the melodies are all over the place. It's a pretty song about an idyllic love that unravels. "I am on a lonely road and I am travelling, travelling, travelling." There was so much sadness around her relationships, but also freedom from them too. As if she's saying, "I won't let you destroy or hurt me. I will triumph in the end with my songwriting and my freedom." I met her four or five years ago at an intimate dinner party, where she held court like a magnificent queen.

Fran Healy, Travis: My Old Man

The piano on My Old Man is like sunshine bursting through leaves and every single line is a perfect observation. "My old man, he's a singer in the park, he's a walker in the rain, a dancer in the dark." And then: "But when he's gone, me and those lonesome blues collide, the bed's too big, the frying pan's too wide." I'm getting teary thinking about how it must feel to have that written about you. To hear it when you've split up must be heartbreaking. Every thread of the album is what happened to her and what she wanted to happen - reflections and projections. I'd never heard anything as honest. It's a perfect album. That's why it's lasted.

Birdy: Little Green

Little Green is about the daughter Joni gave up for adoption as a poor folk singer in Toronto. The guitar is so sweet and light, it makes it almost more sad. And, while the lyrics are veiled, Little Green represents new life and hope. After all she's been through, she just wants the child to be happy. She was so young. To go through that, and then the agony of writing a song about it, just shows what a strong person she is.

KT Tunstall: Carey

I bought Blue when I was 17 or 18 and wore the CD out. She's one of the great guitar players but that's overlooked because her writing and vocal talent is unmatched. Carey [inspired by a red-haired chef she met in Crete called Cary Raditz, whose kitchen exploded] grabs you by the collar and pulls you into a different universe. I can relate to it because she sings: "I miss my clean white linen and my fancy French cologne." That is my life and it's probably how hers was: being on the road with a bunch of blokes and the bus smelling like boys.

She behaved in many ways like a lot of the guys who would have been on the road, just having fun and not getting tied down. Causing trouble basically. She had that wildness in her, a gentle, sweet person actually doing what the fuck she wants. You can hear that in All I Want. "I want to talk to you. I wanna shampoo you." It's just delightful. What guy could resist that?

Carole King: Blue

When the album was released in 1971, I was blown away by Joni's open guitar tunings, unpredictable chord changes, and amazing vocal chops that allowed her to move effortlessly from warm, rich low notes to bell-like high notes and back again. I loved the simplicity of her rhythmic accompaniment on piano, guitar, or dulcimer.

Then I got into the lyrics. It was hard to hear her painfully honest emotions. As a young mother, I found Blue and Little Green especially moving, but then she'd break into something wickedly funny, as in California. The album is such a perfectly sequenced collection of inspired and well-crafted songs that it's difficult to choose one as a favourite. I'll just say to my sister in songwriting: "Congratulations, Joni, and thank you."

Guy Garvey, Elbow: Blue

Between 17 and 30, I was dotting between party houses, bedsits, spare rooms and shared flats. Although I'd never admit it, I was often very scared. Joni was my big sister, my wise, hip auntie and always a reminder what a heartfelt song could do. Blue's title track would touch me most when I was regretting decisions or feeling neglected or just jaded and scared. Something in the first gentle "Hey Blue, here is a song for you" told me she was really worried for who she was singing for. I took it for my own comfort.

These days she's my little sister, knocked out by the world she's moving through, proudly jiving, taking no shit, cooing and wooing her way into all of those hearts. You hear the phrase "free spirit" a lot. This is a perfect recording of one.

Josh Groban: Blue

I've been listening to Blue a lot as we edge out of the pandemic. The really great storytellers like Joni continue to tell our stories in the modern day. We're going through the same experiences and feelings. It's just the details that are different. The album is a perfect 36 minutes, full of unexpected twists and turns. Her piano-playing is so inventive and adventurous. There's a real nothing-to-lose quality about the way she was then.

Blue itself is an extraordinary song. Whether you're in a relationship, breaking up, or you've just lived through the last year in general, everybody is looking into the mirror a little closer to ask: "What am I and who am I without this person?" Blue is the journey to perspective, but she writes songs about being at the other end as well - and falling on her face. It's an absolute masterpiece.

James Taylor: California

Joni had succeeded in music. She had a house and an automobile and wanted to have fun and see the world. After a year or two travelling in Europe with her portable dulcimer, she came back with lots of songs and ideas. We moved in the same circles and ended up together. I'm not saying I was sober, but my then addiction to heroin was relatively quiet.

It was a calm, peaceful, amazing, creative time. She quit smoking and her voice was excellent. She was at the height of her powers. It felt natural and easy for me to play on the album. There were very few people in the sessions. Blue's brilliance lies in its minimalism. It thrives on her voice, melody and personality. It's pure Joni.

California, which she wrote in Paris, is a coming home song. After travelling, your home has a different context within the world and California captures that. It's delightful, personal and genuine. When I was taking her to meet my family in North Carolina, between flights she suddenly said she had to return to California and left me at the airport - at the altar, so to speak. Maybe she sensed the wreckage of my next 15 years and didn't want to be tied down. She is totally real and self-invented and it's one of the best things in my life that I've known her.

Gary Kemp, Spandau Ballet: California

California is a postcard song from her escape trip to Europe. She ended up living in Matala, Crete, with a bunch of cave-dwelling hippies and her dulcimer. It's a wonderfully chatty lyric about her experiences there, good and bad. She'd left Laurel Canyon and Lookout Mountain, but was longing to return to the heartland of the counterculture and pop-making. Yet California was also a place of semi-conscious denial: the opening verse touches on the early realisation, in the 1970s, that peace and love seemed over. The song feels pregnant with those times.

Her return to LA had her falling for James Taylor. Although the relationship left her in despair, he joins her exquisitely on guitar for this difficult yet uplifting song of homesickness and her need to escape back to the garden.

Green Gartside, Scritti Politti: This Flight Tonight

Blue was more beautiful and more sophisticated than any other record of its time. There's not one second that is compromised or ill-judged. Like a rocket trailing an exquisite pyrotechnical display, she took off and transcended her influences, such as Judy Collins and Joan Baez. There are melismatic vocal runs where she sings syllables over extraordinary, twisting runs of notes. They're not folk or jazz or pop, but I think they're among the most incredible things the human voice has ever achieved. I love "Sneaky" Pete Kleinow's pedal steel playing on this song and Joni's restless exploration of guitar tunings gives a gentle dissonance that kind of unsettles. As a teenager, the music sent the most complex and emotionally ambiguous shivers up my spine.

Graham Nash: River

I met Joni in 1967 when I was in the Hollies and we played Ottawa. Later, I flew from London to spend a few days with her in Los Angeles. When I arrived, I could hear voices in the house. David Crosby and Stephen Stills were having dinner with her. The Byrds had thrown David out and Stephen's band, Buffalo Springfield, were over. We smoked a big one and Stephen played this fabulous song, You Don't Have to Cry, with David and myself singing harmonies. So Joni witnessed the birth of Crosby, Stills and Nash.

We were a couple for two years - and I watched her write many of the songs on Blue. She didn't finish it until after we parted. River made me sad, because it chronicled the end of our relationship, but also elated, because it was such a beautiful song and she had the courage to bare her soul. We were very much in love. I treasured that relationship.

I remember leaving the house to give her the space to finish My Old Man. I'm sad that it's about me again, but it's so brilliant. Like the song suggests, I asked her to marry me but I think she thought I wanted a "wife" to cook meals and so on, which was never my intention. I wanted her to be as free as possible, to be as brilliant as possible. She's an amazing woman. I'm proud to have been a part of her life. In 100 years' time, people will remember the Beatles, Bob Dylan and Joni.

Gregory Porter: River

Part of Joni's genius is that it's not always immediately clear where she's coming from. I've heard this played at Christmas concerts, because it begins with: "They're cutting down trees, they're putting up reindeer." Despite the festive imagery, it gradually dawns that she is dreadfully unhappy and she wishes she had a river to just skate the hell away from all the merriment. There's a sophisticated melancholy in her writing and even her public image: not tons of smiling pictures. To me, Joni is always playing with the borders between happiness, sadness, love, hate, sanity and a breakdown, which is where we all are, many times.

David Crosby: A Case of You

Joni went out with me, Graham Nash, James Taylor, Jackson Browne and Leonard Cohen. She was exciting and turbulent and fun and we all loved her - yet I don't think she was ever happy. She'd been through polio, the marriage to Chuck Mitchell and giving up a child - and music was her way of processing this. It could be difficult to be around her because she'd have you laughing or crying real tears in the same half an hour, like her music. It's genuinely who she is.

Bob Dylan's as good a poet as Joni, but nowhere near as good a musician. Paul Simon and James Taylor made some stunners - but for me, Blue is the best singer-songwriter album. Picking a song from it is like choosing between your children. Can you imagine a better song than A Case of You? She was so brilliant as a songwriter, it crushed me. But she gives us all something to strive for.

Jimmy Webb: A Case of You

I saw Joni on stage at the Troubadour in LA in 1968, this golden-haired beauty playing gorgeous chords and singing with mind-blowing abandon in terms of what she was willing to reveal about herself. I wrote her a fan/love letter and sent red roses. Some years later, she found the unopened letter while moving house and said: "I'd love to have tea with you!" We'd become very good friends by then.

She first played A Case of You for me at A&M studios. She was transitioning from guitar to piano and the chords were more modern, complex and dissonant. Lyrically, she was really pushing the envelope in terms of the confessional songwriter. "I could drink a case of you," she sings, "and still be on my feet." She's saying that her love for someone is in her blood like holy wine, but even as she's swept away she's going to survive. Her lyrics were deeply personal revelations, shocking sometimes. She changed how people write songs.

Kim Wilde: A Case of You

As an 11-year-old child who'd never had an alcoholic drink, A Case of You just carried me away. Joni's music and melancholic voice found their place deep inside my heart and the lyrics painted magical pictures in my mind. I would write endless lyrics in notepads inspired by her, but it took several years for me to find the confidence to develop my own songwriting.

One of the loveliest moments of my life was when our musician son Harry bought a lot of old Joni vinyl. I'd hear her tremulous voice drifting down from his bedroom entrancing him just as it had done me so many years before.

Holly Macve: The Last Time I Saw Richard

I was 18 and had just moved into an empty flat in Brighton. I'd been doing some pop co-writing which wasn't really me. I felt like I'd lost myself. Blue helped me find my own voice. The Last Time I Saw Richard was sparked by a conversation she had with folk singer Patrick Sky. It's a philosophical argument between a romantic idealist and a cynical realist. As a dreamer myself, it has my favourite line on the album: "Go look at your eyes, they're full of moon." Then she sings: "You got tombs in your eyes, but the songs you punched are dreaming." It's a novel in four minutes. Just breathtaking.