Ray Manzarek, the Doors keyboardist who brought both a light jazz touch and some seriously heavy piano-pounding to one of the most influential American bands of the late '60s and early '70s, passed away earlier Monday, according to CBS News. He was 74.

By most accounts, including the one in Oliver Stone's 1991 biopic The Doors (though Manzarek was no fan of the movie, to say the least), it was Manzarek who was most responsible for the band's formation, convincing his fellow former UCLA student Jim Morrison to channel his poet/shaman/lizard-king talents into rock and roll.

Manzarek's keyboard parts could vary wildly from song to song, but were always central to the arrangement; think of songs as diverse as "Hello, I Love You" and "Love Me Two Times" to "Riders On the Storm" and "The Crystal Ship." His best-known moment may have been his swirling, psychedelic organ solo in the Doors' breakthrough hit "Light My Fire," but personally we always preferred the more barrelhouse style Manzarek brought to songs like "L.A. Woman" and "Roadhouse Blues." His steady left hand eliminated the need for a bass player, one of the Doors' less publicized innovations.

In many ways the Doors represented the dark, dangerous side of the rock and roll fantasy, almost the polar opposite of their sunny Southern California neighbors the Beach Boys, and they went on to influence bands ranging from Iggy and the Stooges to Echo and the Bunnymen. But in the late '60s, when rock was losing ground to UK bands like Led Zeppelin at a serious clip, the Doors held serve and all but founded the Sunset Strip scene that later bands like Van Halen and Guns N' Roses would mine so lucratively.

But the bespectacled Manzarek remained a musician's musician. He tried a solo career in the '70s to no great success, but went on to produce X's Los Angeles, one of the greatest punk records of the '80s - and one of the best L.A. albums of all time, right up there with a few Doors records. His 1998 memoir Light My Fire, My Life With the Doors, became a best-seller, and he eventually reconvened some of the Doors' surviving members and struck out on the road as The Doors of the 21st Century.

Manzarek died after a long struggle with bile duct cancer, according to a statement released by his publicist Heidi Ellen Robinson-Fitzgerald. He had been seeking treatment at the RoMed clinic in Rosenheim, Germany, and his family is said to have been at his side.