The Foo Fighters career has been, as even its members concede, an unlikely one. Starting out with a handful of self-recorded demos never meant for release, former Nirvana drummer Dave Grohl has grown the group into one of rock's most energizing and accessible acts, scoring Best Rock Album Grammys for two consecutive releases There Is Nothing Left to Lose and 2002's One By One) and selling out concerts around the world.

To celebrate its 10 th year of existence - and to thank its numerous fans - Grohl hit upon the plan to make its fifth album, In Your Honor (RCA), a double disc. And if that wasn't enough, he decided the album would be evenly split between one hard rocking set and one acoustic, more introspective one.

"By splitting the difference," he explains, "you eliminate the middle ground. We can make the acoustic record far more delicate and beautiful and atmospheric than anything we've ever done, and we can make the rock record far more brutal and aggressive and powerful than anything from our past. I've always sort of believed we were capable of doing both - just not as well as this has turned out.

Indeed, In Your Honor has received critical hosannas across the board, with comparisons to Led Zeppelin's double album Physical Graffiti making practically de rigueur appearances in reviews. Ranging from the intensely personal single "Best of You" and the throbbing title track, to quieter numbers like "Still" and "Friend of a Friend" - the latter apparently a tribute to the late Kurt Cobain - the release comes off as two very distinct records, albeit of one dedicated mind.

"Everyone in the band has so much to offer," Grohl says of fellow Foos Nate Mendel (bass), Taylor Hawkins (drums) and Chris Shiflett (guitar). "But we'd sort of remained in this one 'thing' for so long that I felt it was time to break out, to branch out, that maybe we should make the acoustic record. But then this band just has to make some rock music so I thought, "Okay, why don't we do this? Why don't we make a double album?

Throw in an impressive range of guest stars - from Norah Jones on "Virginia Moon" and "Queens of the Stone Age" leader Josh Homme on "Razor" to Zep's own John Paul Jones on "Miracle" and "Another Round," and you have a work that's musically beefy yet also just fun to listen to, as is the case with the best of the Foos.

"In 20 years, when some kid asks his dad, 'You ever hear of Foo Fighters? Which record should I get?' they should say In Your Honor," Grohl affirms. "I want people to say, 'Wow, that's the album they'll be remembered for.'"

MusicWorld story by Kevin Zimmerman