Rock pioneer Lou Reed died today at the age of 71, according to Rolling Stone.

While the cause of death is still unknown, Reed had undergone a liver transplant in May.

Louis Allan "Lou" Reed was born in Brooklyn in 1942. He earned his undergraduate degree from Syracuse University, where he studied journalism, creative writing, and hosted a late-night radio program.

Reed moved to New York City in 1964, where he began working as a songwriter for Pickwick Records. After befriending John Cale, Reed and two of his college friends, Sterling Morrison and Maureen Tucker, started The Velvet Underground. With the help of Andy Warhol and German songwriter Nico, the band debuted with The Velvet Underground & Nico.

The core foursome would become know for such melancholic songs as "Sunday Morning" and "Sweet Jane." And while the band was unstable and flew well below the radar at the time, The Velvet Underground would eventually become one of the greatest musical influencers and cult favorites of the 20th century. In 1996, the band was inducted into the Rock and Roll Hall of Fame.

In the early 1970s, Reed broke out on his own and into the mainstream with his hit single "Walk on the Wild Side." Despite a few stand-out commercial successes, Reed's career followed the jagged trajectory of his own musical curiosities that would often lead him far from his rock roots and into such musical genres as classical, comedy, and ambient noise.

But Reed eventually returned to rock with 2011's Lulu, a collaboration with Metallica, which divided fans and critics alike. Reed, forever a curmudgeon toward the press and his critics, told The Telegraph in 2011 that his work was never about what other people wanted anyway.

"Who cares?" said Reed when Telegraph writer Neil McCormick mentioned Lulu's critics. "I never wrote for them, I don't write for them now. I have no interest in what they have to say about anything. I'm interested in whether I like it. I write for me."