Blue was the first Joni Mitchell record I ever heard - probably a representative experience for fans that came to her music decades after its release. I haven't appreciated her work chronologically, and there are definitely songs I've missed or been unmoved by, but Blue in its entirety sticks significantly in my mind as sounding unlike anything else I'd heard before. Unlike anything else, despite it being a 35-minute, 10-song thing with a sparse approach to instrumentation, nothing obviously experimental or 'out there' about it and 30 years between its creation and my 14-year-old self listening to it.

Three studio albums in, it marked a shift in Mitchell's approach to songwriting; it's a collection of songs with, as she herself put it in a 1979 Rolling Stone interview, "hardly a dishonest note in the vocals. [...] I felt like I had absolutely no secrets from the world and I couldn't pretend in my life to be strong. Or to be happy. But the advantage of it in the music was that there were no defenses there either."

The honesty and defenselessness that characterise Blue were the result of two relationships ending, and Mitchell taking herself off around Europe and then into the studio to make sense of what had happened - and they carry through into her explanation of the song-writing process, too: "In the state that I was at in my inquiry about life and direction and relationships, I perceived a lot of hate in my heart. You know, 'I hate you some, I hate you some, I love you some, I love you when I forget about me' ('All I Want'). I perceived my inability to love at that point. And it horrified me. It's something still that I...I hate to say I'm working on, because the idea of work implies effort, and effort implies you'll never get there. But it's something I'm noticing."

It's this song, 'All I Want', that kicks off the album. It's a stomper, full of energy and questions - but the lyrics betray a loneliness and open insecurity that the music risks concealing on a first listen. We might be used to love and break-up songs that are flavoured with vulnerability, but I certainly had never come across something like this. "All I really really want our love to do / Is to bring out the best in me and in you / I want to talk to you, I want to shampoo you/ I want to renew you again and again" and "Do you see / How you hurt me baby?/ So I hurt you too / Then we both get so blue". In its relentless honesty, it invites the listener in - it makes us feel as though anything goes, nothing is forbidden, you don't have to pretend to feel stronger or more 'together' than you do right now. She puts her cards on the table first, which allows us to freely settle into our grief, confusion, excitement - whatever - with her.

'My Old Man' tells of love that doesn't need making official and the void that appears every time she's apart from him. These aren't exactly untrodden subjects for love songs, but it's the words she uses that hit you right in the stomach and make it do huge, unanticipated flips: "But when he's gone / Me and them lonesome blues collide / The bed's too big / The frying pan's too wide" and "He's the warmest chord I ever heard". Her songs might transport you to specific places and moments you've never been to or in, but the feelings are universal - and she writes about them in a way that makes you say: "Yes, I've never thought about it in that way, but that's exactly how it is."

The title track 'Blue' begins "Songs are like tattoos" and goes on to say "Underneath the skin / An empty space to fill in". In the context of this album, it's as though she's compelled to write to replace a void that was previously filled by something or someone else - the creation of these songs is all about healing and having to build a new personal reality.

But an entirely heartbreak-fuelled album this is not: 'Carey' and 'California' both chart Mitchell's adventures around Europe; both are clever, funny, full of romance, wanderlust and homesickness. 'Little Green' is about Mitchell giving her daughter up for adoption - so yes, heartbreak lurks there too, but in a different way. It's quieter, more private, a mix of hope, regret and acceptance.

'River' and the penultimate track 'A Case of You' sit beside one another - similar only in their craft and beauty. While the former turns a Christmas carol firmly on its head - 'Jingle Bells' will never sound jolly again - the latter is about the heady intoxication of love. That's literal intoxication, too: "I could drink a case of you, darling / And I'd still be on my feet". But later in this song come the words that had me staring into the distance and wearing out the rewind button and attempting, with very little success, to write songs of my own: "I remember that time you told me, you said / 'Love is touching souls' / Surely you touched mine / 'Cause part of you pours out of me / In these lines from time to time". And, 45 years on, it's still in these lines that we all see part of ourselves.