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Sad news for classic rock fans: The Doors' Ray Manzarek passed away this morning from complications related to bile duct cancer. The highly influential keyboardist was 74.

The Doors were one of the most acclaimed, beloved and successful rock acts of the '60s and early '70s. Given the band's lack of a bassist, Manzarek's keyboard playing—which touched upon jazz, psychedelia and classical music—was a defining element of the band's sound. 

Manzarek contributed vocals to two Doors albums released after Jim Morrison's death as well as singing lead on "(You Need Meat) Don't Go No Further," the b-side to "Love Her Madly."

In addition to forming the group Nite City with Blondie bassist Nigel Harrison in the late 1970s, Manzarek released six post-Doors solo albums and produced four classic punk albums from L.A. outfit X during the '80s.

In 2002, 31 years after Morrison's death, Manzarek and Doors guitarist Robby Krieger reunited and began touring as The Doors of the 21st Century with the Cult's Ian Astbury on vocals. The band was forced to change their name to Manzarek-Krieger after original Doors drummer John Densmore filed a court injunction against his former bandmates.

Manzarek is survived by his wife, son and three grandchildren.