JD Souther, the country-rock singer-songwriter who helped write some of the Eagles’ biggest hits, has died. As The Los Angeles Times reports, an Eagles representative confirms that Souther recently passed away at his New Mexico home. He was scheduled to start a solo tour next week. Souther was 78.

John David Souther was born in Detroit and mostly raised in Amarillo, Texas. As a young man, Souther formed a mid-’60s rock ‘n’ roll band called the Cinders, and one of their singles came out on Warner Bros. under the name John David And The Cinders. Souther moved to Los Angeles and became close friends with fellow Detroit native Glenn Frey. Before Frey joined the Eagles, he and Souther had a folk duo colled Longbranch Pennywhistle, and they released one album in 1969. After that, Souther released a 1972 solo album and then formed a new group with Chris Hillman, formerly of the Byrds, and Richie Furay, formerly of the Buffalo Springfield. The Souther-Hillman-Furay Band released a couple of albums in the mid-’70s, and they had a minor hit with their 1974 song “Fallin’ In Love.”

When Glenn Frey and Don Henley were playing in Linda Ronstadt’s backing band in the early ’70s, Souther was dating Ronstadt. Souther produced Ronstadt’s 1973 album Don’t Cry Now and wrote her 1974 country single “Faithless Love.” When the Eagles first formed, Souther considered joining the band, and they practiced with him a few times. He never became an Eagle, but he did become one of the band’s most important collaborators. Souther co-wrote three of the Eagles five #1 hits: “Best Of My Love,” “New Kid In Town,” and “Heartache Tonight.” Souther also worked with plenty of other acts around that time, including Bonnie Raitt, Dan Fogelberg, and Christopher Cross. James Taylor and JD Souther recorded the 1981 duet “Her Town Too,” a song that the two of them co-wrote with Waddy Wachtel, and it reached #11 on the Hot 100.

While he was working with all these other artists, JD Souther continued to release his own solo recordds, and he reached #7 with the 1979 single “You’re Only Lonely.” In the ’80s, Souther worked with Roy Orbison and Clannad, and he co-wrote Don Henley’s 1989 single “The Heart Of The Matter.” Souther sang the Platters’ “Smoke Gets In Your Eyes” in the 1979 Steven Spielberg movie Always. That led to a bit of an acting career, and Souther took roles in the TV shows Thirtysomething and Nashville and the movies Postcards From The Edge and My Girl 2. He also wrote the theme music for the Richard Lewis/Jamie Lee Curtis sitcom Anything But Love and co-wrote “Doin’ Time For Being Young,” a song that Johnny Depp performed in the John Waters film Cry-Baby.

In 2008, JD Souther released If the World Was You, his first solo album in 24 years. He released a few more solo records after that; the most recent was 2015’s Tenderness. Souther was inducted into the Songwriting Hall Of Fame in 2013. This past January, Don Henley welcomed Souther to the stage during an Eagles show at the Kia Forum, calling him an important part of their “tightknit community of songwriters and singers.”

The Eagles have shared a eulogy:

We have lost a brother, a friend and a brilliant collaborator, and the world has lost a great songwriter, a pioneer of the Southern California sound that emerged in the 1970s. J.D. Souther was smart, talented, well-read, and in possession of a wicked sense of humor. He loved a good meal, a good movie, and a good Martini … and he loved dogs, adopting many, over the course of his lifetime. Born in Detroit and raised in the Texas Panhandle, he was a student of the deep roots of the best American music – from country, to jazz, to classical, as well as “Standards” from the Great American Songbook – and that knowledge and appreciation informed his work. He was a crucial co-writer on many of our most popular songs, including, The Best of My Love, New Kid in Town, and Heartache Tonight. J.D. also collaborated on many of Don Henley’s solo works, including The Heart of the Matter, Little Tin God, If Dirt Were Dollars and Talking to the Moon.

We mourn his loss and we send our condolences to his family, his friends, and his many fans around the world. He was an extraordinary man and will be greatly missed by many.

Adios, old friend. Travel well.

The Eagles

Check out some of Souther’s work below.