(Page 2 of 2)

Rock, with a history of iconoclasm and distrusting authority, did not have such a unanimous reaction. An all-star remake of Marvin Gaye's ''What's Going On,'' which declares, ''War is not the answer,'' had been in the works to benefit AIDS research; after Sept. 11, part of its proceeds were redirected to the United Way's Sept. 11 Fund. Some rock listeners unleashed vicarious rage with pre-existing songs like System of a Down's ''Chop Suey.'' But others sought reassurance in John Mellencamp's ''Peaceful World,'' U2's ''Stuck in a Moment You Can't Get Out Of'' and Enrique Iglesias's ''Hero.'' Ryan Adams had made the video clip of his ''New York, New York'' standing in front of the twin towers; after Sept. 11 what had been a breakup song become an elegy.

The two rock benefit-concert albums are snapshots of changing responses. ''America: A Tribute To Heroes'' captures the initial shock and sadness that followed the attacks. It's a spectrum of mourning, patriotism, anger, pacifism, praise for heroes and a longing for love and peace, full of heartfelt contradictions. Tom Petty glares into the camera and calmly vows, ''I won't back down''; Sting denounces violence in ''Fragile.'' Neil Young sings John Lennon's ''Imagine,'' dreaming of an end to nationalism and religion; U2, in ''Walk On,'' sings ''Alleluia.'' Bruce Springsteen's ''My City of Ruin,'' written before the attacks about a decrepit New Jersey seaside town, suddenly seems to depict ground zero. With little celebrity gloss, the musicians come across as humble, searching for the song that will say the right thing.

There were fewer questions and more pumping fists a month later at the Concert for New York City, where pop and rock stars played to an audience full of police and firefighters at Madison Square Garden. The Who blasted ''Won't Get Fooled Again,'' while Bon Jovi aimed ''Wanted Dead or Alive'' at Osama bin Laden. The concert's finale is Paul McCartney's ''Freedom,'' an old-fashioned singalong that tries to rally the troops around a campfire, but it hasn't caught on.

Hip-hop has been slow to address the attacks, but one song has made headway: ''Ground Zero (In Our Hearts You Will Remain)'' by Cash & Computa. Set to a snippet of a Stevie Wonder song, it ricochets from sadness -- ''this is like something that you see in a movie/ but it's real the pain us Americans feel'' -- to fury: ''No hesitation, we bomb first make you eat dirt.'' The Wu Tang Clan's new album, ''Iron Flag,'' completed after Sept. 11, applies standard braggodocio to the events, warning terrorists that they'd never survive in the group's neighborhood.

Mr. Young's ''Let's Roll'' may be the first song to envision the events from inside. It is a long way from the wistful generalities he sang a few months earlier with ''Imagine.''

Making his narrator one of Flight 93's passengers, he sings in a gruff, choked voice: ''I hope there's someone who can fly this thing and get us back to land,'' and later, ''No one has the answer, but one thing is true/ You've got to turn on evil when it's coming after you.'' Beginning as a topical song, ''Let's Roll'' turns into a moral parable.

Popular culture is always most at home in a clear-cut conflict between good guys and bad guys. Music has now enlisted in a role that has been unfamiliar for as long as most of its stars have lived: providing not just solace, but solidarity.