R.E.M.'s Jackknife Lee-produced 14th studio album, Accelerate, lives up to its speedy title. It's loud, quick and dirty, spinning by so fast that it takes multiple listens to absorb. It's full of buzzing guitars and stream-of-­consciousness discontent, along with an abundance of Mike Mills's choir-boy harmonies and sinewy bass. And naturally, it hints at the Athens, Georgia, band's past — fuzzy riffs à la 1994's Monster (the title track); the dirty distortion and droning yowls of 1988's Green ("Mr. Richards"); orchestrated elegance circa 1992's Automatic for the People ("Houston"); and the slick political earnestness of 1987's Document ("Until the Day is Done"). Yet the amped-up atmosphere of Accelerate is unique within R.E.M.'s catalog, and doesn't resemble the mood of previous releases — meaning that you can't exactly herald it as a return to form (whatever that means, anyway).

If Accelerate has an overarching theme, it revolves around keeping youthful idealism alive. Instant classic "Hollow Man" begins with somber piano and a vulnerable Stipe gruffly singing, "I've been lost inside my head / Echoes fall on me." But crashing guitars suddenly bulldoze the chorus and eventually emerge triumphant, mirroring the narrator's wild-eyed regret at his life — and his burning desire to transcend his status as a "hollow man." The hand-wringing protagonist of "Houston" is only stunned, not destroyed, by challenges to his faith after Hurricane Katrina.

Despite such weighty matters, what stands out most is that R.E.M. is having fun again, after several strained-sounding releases. On Accelerate, R.E.M. stops over-thinking things — and roars forward into the future.