This month, country music royalty Emmylou Harris and Rodney Crowell released a beautiful collection of duets, The Traveling Kind. Harris has 13 Grammy wins, while Crowell has two of his own and handful of No. 1 hits. But both of them may best be known for the work they’ve done with others: Harris, from her duets with Gram Parsons and her interpretations of Crowell’s songs. And Crowell, whose writing has a distinct literary quality, earned Top 10 hits for everybody from Johnny Cash and Waylon Jennings to Keith Urban. Despite a close personal and professional relationship, Harris and Crowell waited almost 35 years before recording their first duets album, 2013’s Old Yellow Moon, a Grammy winner. The songs on The Traveling Kind are simple and piercing; they’re about lost love, fate, the beauty and cruelty of life. The real intimacy is revealed in Crowell’s and Harris’s singing. They took time out this week to tell vanityfair.com the backstory of one of the most storied collaborations in country music.

Emmylou Harris: My relationship with Rodney goes back to 1974. I was working on my first solo record. I spent an entire day with my producer, Brian Ahern, listening to songs for us to record and I didn’t really like anything that he was playing for me. We went through a whole stack of tapes and there just wasn’t anything. He had just received a tape from Rodney, so we opened it up and heard “Blueberry Wine” for the first time. It was exciting to hear something you really loved. Rodney’s voice is so unique. There was something about the energy in the songs. It was real. It was from the heart. So I said, “I love this. I love this.” We had to locate Rodney, and of course he was like a wandering boy at the time. He was down in Austin. We tracked him down and flew him to Washington, D.C. I was still playing clubs back then. He sat in with my band at this little club by Dupont Circle.

Rodney Crowell: You should have seen her up on that stage, playing with that band. Just a vision and singing like a bird. Being a young man of 24, I thought, I’m going to make a pass.

Harris: The next day we got together at a friend’s house and he sang me “Until I Gain Control Again.” We loved to sing together from the very beginning. We love the same kinds of songs.

Crowell: My eyes and my heart opened up in such a way that I could see that this was going to be a friendship. Add to that the fun we had working. The work was fun. We traveled around like giddy school kids in our mid-20s. We went to England for the first time and stayed at the Hyde Park Hotel. We were just high-rollin’ hillbillies.

Harris: We traveled with Elvis Presley and his band. There were some tried and true musicians in that outfit. We became a family through playing music we loved and hanging out together. Everybody had a really unique sense of humor. We fed off each other in a very positive way. It set the standard for me—no egos or stuff like that to deal with. We’re out here serving the music, not to make it sound too grand.

Crowell: The first song where I thought, That’s it, and I got the blessing from Guy Clarke and Townes Van Zandt, was a song called “Song for the Life.” That was the first keeper I wrote. I was 22. The process is still revealing itself today. I still feel like I’m gonna paint my masterpiece someday.

Harris: I haven’t kept track of how many of Rodney’s songs I’ve recorded. Something about them suits me. He writes the truth. You have a truth meter. You just know when the words get your chakras going. Rodney’s writing has always done that for me. I got first crack at a lot of those songs before the world discovered him.

Crowell: Early on, Emmylou recorded three or four of my songs and had hits. My career as a songwriter started to blossom. I sat down one day and spent an entire day writing a song for Emmylou. When it was done, I went to her house and said, “Hey, Emmy, I wrote a song for ya!” I pulled out my guitar and played the song. She said, “That’s really nice, but man, I heard a demo for your song ‘You’re Supposed to Be Feeling Good’—I want to record that.”

Harris: I can’t even remember the name of that song. All I can remember is that I wanted to record the other one he wrote me.

Crowell: If you’re patient enough, a song will tell you what it wants to be. If I said, “Well, I’m going to write a blues song for Emmylou,” then the cart is ahead of the horse. And the truth doesn’t get through. It’s a mental process to create something when the real language of timelessness comes from the heart. That’s the only time I tried to write a song for somebody.

Harris: We loved to sing together from the very beginning. We love the same kinds of songs. We had for a duet album in 1974, when we first met. Rodney was in the Hot Band for three years, then he went on to his solo career.

Crowell: Collaboration is a vital part of my creative life. I’ve had success with Guy Clark and Waylon Jennings and Johnny Cash. I started writing a memoir and Mickey Raphael from Willie [Nelson]’s band heard that I was messing with it, trying to write sentences and paragraphs, and he gave me Mary Karr’s book The Liars’ Club. It made all the sense in the world to me; we’re from the same part of Texas. Our childhoods were so parallel. I put Mary’s name in a song and waited for awhile and then I sent her a letter that said, “Hey, since I’m the guy who is bandying your name about, thought I’d introduce myself.” She wrote back saying that the song had really improved her street cred. We became fast friends, and then I said, “We need to write some songs together.” She dragged her feet. Then one day she got interested, and we just caught on fire. We wrote 15 songs in our spare time in less than a year. It became a record.

Harris: You never know what’s going to happen. The real attraction to collaboration is that you want some of what the other person’s got. It’s a great energy field to be around.

Crowell: Singing duets is instinctive, intuitive. Really born out of family and rooted in the church. Duet partners that rose up going back to the Louvin Brothers, the Blue Sky Boys, the Delmore Brothers.

Harris: I was the one that finally called Rodney about doing our first album of duets, Old Yellow Moon. I said, “You know that record we’ve been talking about for 35 years or so . . .” We put a golden circle around the dates. We had to make time for ourselves.

Crowell: We went to Brian Ahern’s house. He did Emmy’s first 10 or 12 albums. We sat at his kitchen table and started talking. We didn’t know what we were going to do. We just had a conversation.

Harris: Rodney had a big list of songs. I had just had “Old Yellow Moon,” which was written by a friend. I had it for 10 years on a list of songs that I had to record. I’m so glad I waited because it had to be a duet between two old friends. That was the missing piece. The first time Rodney and I ever sang it together, Brian recorded it at the kitchen table. That’s the version on the album. Just two acoustic guitars and two voices. Rodney was reading the words off the page. The other instruments were added later.

Crowell: Old Yellow Moon was a great record and there was a lot of good will out there for us. But if you try to capitalize or build on it in an intellectual way, then you’re probably going to fall on your face. But if you follow you’re heart, it’s going to go a lot farther.

Emmylou: With this album Rodney said, let’s write it together. I hesitated. He had invited me in and of course I was going to go there. But I always worry that I’m not going to be able to come up with anything on the fly. I didn’t come with any ideas. I went in with a complete blank slate.

Crowell: Traveling Kind is about our shared sensibilities. We don’t try to project ourselves as this romantic couple singing together. Writing became about rolling up our sleeves and sharing our sensibilities. Working with Emmylou makes me a better songwriter. She has the heart of a poet, and when she gets going you can’t stop her. She knows language. She knows what’s true and understands that you have to keep digging.

Harris: Writing can be terrifying for me. Now I just think that I’m in good hands. If I come up with a line that isn’t quite right, I know that Rodney will call me on it. I’m not afraid to say something stupid because I know now that you have to get it all out there.

Crowell: There’s a song on the new album called “Higher Mountains.” I started it a long time ago, when my father died and left my mother alone in Texas. I had the first two verses, but then it was parked for 17 years, and when Emmy and I started working together that song started coming up for me. I found the old tape, dug it out of moth balls. Emmy’s mother was approaching the end of her life.

Harris: My father died in 1993 and my mother came to live with me, so she was another partner left behind, like Rodney’s mother. I could really relate to where that song was coming from. How he could visualize what his mother’s inner life was like without her husband. I saw it every day with my mother. She was so generous and loving and she didn’t overwhelm us with her grief. I knew in her way that she was longing for my father because they had 50 years of true marital bliss, and Rodney’s parents had one of those marriages that survives the slings and arrows of life. We had that in common with what we were trying to get to, what we were trying to say with that song.

Crowell: I couldn’t push it any farther than it went. Something told me, Emmy can bring this home. Seventeen years in between. I think that’s pretty cool.