What was R.E.M.

? It depends on who you are. Outside of U2, the Athens, Ga., quartet was the biggest rock band on the planet in the 1990s.

But for those who followed its early career as America’s most popular indie-rock band in the ’80s, R.E.M.

’s popularity came as something of a culture shock , with their cult heroes now being piped into suburban malls and playing in rotation on classic rock radio stations. In the prestreaming age, when the music landscape was dominated by major record labels and a rear-guard of small labels scattered around the country, R.E.

M.’s move from indie I.R.

S. to Warner Bros. Records was seen as a betrayal by many who had regarded the quartet as music industry outliers.

Peter Ames Carlin, author of the new biography “The Name of This Band Is R.E.M.

,” is having none of that. “More than any other band, R.E.

M. symbolized that moment at which college radio morphed into this more label-driven thing, and I understand that fans felt betrayed,” says Carlin from the Seattle home he shares with his partner, writer Claire Dederer. “But for any artist to achieve personal progress, you’ve got to grow and change, and that’s what R.

E.M. did.

” “The Name of This Band Is R.E.M.

” carefully tracks the band’s remarkable trajectory from kegger parties in the college town of Athens during the early ’80s to global ubiquity and its slow burn into dissolution in 2011. The story neatly cleaves into two distinct eras. The four band members found .