Steely Dan co-founder Walter Becker, the bassist, guitarist and arranger who co-wrote classics such as “Do It Again,” “Rikki Don’t Lose That Number” and “Hey Nineteen,” died Sunday. He was 67.

Becker’s death was reported on his website with no details.

Becker, who played bass in the early incarnation of the band and guitar for the group after their re-formation in 1993, had missed this summer’s Classic West and Classic East concerts in Los Angeles and New York. Prior to the concerts, his partner in Steely Dan, Donald Fagen, said "Walter's recovering from a procedure and hopefully he'll be fine very soon" without providing any details.

Becker last performed with Steely Dan during their nine-show residency in Las Vegas in April. Steely Dan is scheduled to perform in Dublin and London in October.

In a statement, Fagen said, “I intend to keep the music we created together alive as long as I can with the Steely Dan band.”

Becker and Fagen met at New York’s Bard College in 1967 and started collaborating as songwriters in various bands. In 1969, they signed a music publishing deal—Barbra Streisand recorded their “I Mean to Shine”—with a company owned by Jay and the Americans, which they would join as their backing musicians.

That led to the duo signing on as staff songwriters at ABC/Dunhill in 1971 and moving to Los Angeles. Using a collection of studio musicians that included guitarist Jeff “Skunk” Baxter and singer David Palmer, they recorded a collection of songs and named the band Steely Dan and the album Can’t Buy a Thrill. It would yield their first two hits: “Do it Again” and “Reelin’ in the Years.”

Steely Dan has a revolving door of members over their next two albums and tours—Michael McDonald and Toto’s Jeff Porcaro among them—before Becker and Fagen gave up touring and worked strictly with studio musicians.

That started with 1975’s Katy Lied and would continue on Aja, their biggest seller, The Royal Scam and Gaucho. They were a musically advanced unit that incorporated elements of jazz, reggae and classic pop hooks that distinguished them from all other acts in the 1970s; they were also one of the few acts to have hits in the decade with multiple lead singers.

While they evolved stylistically, impeccable production and engineering were consistent , and even defining, elements of their records. Lyrically, they were darkly humorous and, at times, covert.

The two split up in 1980 and Becker moved to Hawaii to be an avocado farmer and producer, making albums with Rickie Lee Jones, Krishna Das and assorted jazz musicians; he produced Fagen’s Kamakiriad in 1993 after returning to performing in 1992, joining the tour of Fagen’s New York Rock and Soul Revue.

The following year, Fagen and Becker toured as The All New Steely Dan Orchestra, which evolved in Citizen Steely Dan Orchestra in 1994, the year Becker released his debut solo album 11 Tracks of Whack.

They continued to tour globally as Steely Dan and, in 2000, Irving Azoff’s Giant Records released Two Against Nature, the first Steely Dan album in 20 years. Becker won three Grammy Awards for the album, including Album of the Year, and its single "Cousin Dupree."

The band was then inducted into the Rock and Roll Hall of Fame and the two were honored with doctor of music degrees from Berklee College of Music.

Becker released a second solo album, Circus Money, in 2008, Steely Dan released their last album, Everything Must Go (Reprise) in 2003 and toured regularly through 2016.

Fagen’s statement read, “Walter Becker was my friend, my writing partner and my bandmate since we met as students at Bard College in 1967. We started writing nutty little tunes on an upright piano in a small sitting room in the lobby of Ward Manor, a mouldering old mansion on the Hudson River that the college used as a dorm.

“We liked a lot of the same things: jazz (from the twenties through the mid-sixties), W.C. Fields, the Marx Brothers, science fiction, Nabokov, Kurt Vonnegut, Thomas Berger, and Robert Altman films come to mind. Also soul music and Chicago blues.

“Walter had a very rough childhood—I’ll spare you the details. Luckily, he was smart as a whip, an excellent guitarist and a great songwriter. He was cynical about human nature, including his own, and hysterically funny. Like a lot of kids from fractured families, he had the knack of creative mimicry, reading people’s hidden psychology and transforming what he saw into bubbly, incisive art. He used to write letters (never meant to be sent) in my wife Libby [Titus'] singular voice that made the three of us collapse with laughter.

“His habits got the best of him by the end of the seventies, and we lost touch for a while. In the eighties, when I was putting together the NY Rock and Soul Revue with Libby, we hooked up again, revived the Steely Dan concept and developed another terrific band.”