(CNN) -- Lou Reed, who took rock 'n' roll into dark corners as a songwriter, vocalist and guitarist for the Velvet Underground and as a solo artist, died Sunday, his publicist said. He was 71.
The publicist, Peter Noble, confirmed Reed's death but released no details. Reed had undergone a liver transplant in May, his wife, the musician/performance artist Laurie Anderson, disclosed over the summer.
Reed was a rock pioneer who went from record label songwriter to a member of the short-lived but innovative and influential Velvet Underground. The band and Reed's solo work tackled taboo topics like drug addiction, paranoia and sexual deviancy in songs that were largely spare, muscular and often saturated in feedback.
"Lou Reed's influence is one that there are really only a tiny handful of other figures who you can compare to him," said Simon Vozick-Levinson, a senior editor at Rolling Stone.
"He spoke incredibly frankly about the realities of being an artist, being a person who lived life on one's own terms. He didn't prettify things. He didn't sugarcoat things. He showed life as it really is and that's something that made him a true original, and one of our great all-time artists," he said.
Reed, violist/keyboard player John Cale, guitarist Sterling Morrison and drummer Maureen Tucker played their first show as the Velvet Underground in 1965 and soon drew the attention of pop artist Andy Warhol, who became their manager. Rock mythology has it that even though the group sold few albums, everyone who bought one started a band.
"We had fans who made us realize it was worth it," Tucker told CNN. "But when we were together, actively, we didn't have a big splash like the Doors or whatever."
Nevertheless, Rolling Stone ranks the group's debut album, "The Velvet Underground and Nico," as the 13th greatest of all time. Tunes like "Sweet Jane," from the group's 1970 album "Loaded," have become rock standards. Performers from David Bowie to R.E.M. and U2 have cited them as inspiration, and the Velvet Underground was inducted into the Rock and Roll Hall of Fame in 1996.
"The world has lost a fine songwriter and poet. I've lost my 'school-yard buddy,' " Cale wrote on Twitter.
Tucker called Reed "generous, encouraging and thoughtful." Working with him "sometimes could be trying" to some people, but "never to me."
"I guess we learned from each other. We all learned from each other," she said.
In 1970, Reed left the Velvets for a long solo career. He had his only Top 40 hit with "Walk on the Wild Side," from the Bowie-produced 1972 album "Transformer," and Rolling Stone put both that album and 1973's "Berlin" on its top 500 list.
Reed "was one of the first artists to experiment with guitar feedback on record and to show that sort of ugly noise can actually be quite beautiful and moving. He also, lyrically, wrote about all kinds of topics that were taboo before he started exploring them," said Vozick-Levinson.
He also gave a voice to gay and transgender people in a way that had never been done before by a popular artist, which made his work incredibly important to many people, Vozick-Levinson said.
In 1982, Reed told The New York Times that his goal wasn't just to make music, but create literature.
"People say rock 'n' roll is constricting, but you can do anything you want, any way you want,'' he said. "And my goal has been to make an album that would speak to people the way Shakespeare speaks to me, the way Joyce speaks to me. Something with that kind of power; something with bite to it."
And Tucker said Reed "influenced probably millions of people into maybe reading more, into playing music."
"When I have been on tour, there have been kids from 15 years old to 60 years old commenting on how they were influenced by Lou and the Velvets," she said.
The rock band the Pixies wrote on their Twitter page, "R.I.P. LOU REED....A LEGEND." Iggy Pop wrote simply: "Devastating news."
Reed won a Grammy award in 1998 for best long-form music video, for a documentary on his career up to that point. Neil Portnow, president and CEO of The Recording Academy, called him "an exceptionally gifted singer, songwriter, and musician who has had a profound impact on rock music and our culture,"
"We have lost a true visionary and creative leader, and his groundbreaking work will forever hold its rightful place in music history," Portnow said.
CNN's Denise Quan contributed to this report.