Anytime an artist that can't be categorized strictly as "rock" gets attention from the Rock Hall, there's an outcry from certain vocal fans.

Jim Henke, Rock and Roll Hall of Fame Nominating Committee member, gives his justification for induction a pop star such as Madonna:

"To me, it's the same issue as last year with Grandmaster Flash and `does hip-hop belong in?'" says Jim Henke, vice president of exhibitions and curatorial affairs at the Rock and Roll Hall of Fame and Museum in Cleveland. "I think here at the museum and among other inductees, we've always defined rock and roll pretty broadly.

"It's not just about four guys with guitars or something like that. Madonna certainly had a huge impact on popular music and rock `n' roll throughout the `80s and `90s and she's certainly deserving of being honored."

Henke points to Madonna's music, her incorporation of dance elements and her mixing of styles that influenced lots of performers that came after her.