Now that the music on In Rainbows has had four years to outshine its launch mechanism, it's easy to forget that the album originally came bundled with an honest attempt to solve a business problem. The pay-what you-think-is-fair system wasn't just Radiohead being magnanimous, it was using their popularity and their newly won independence to ask what might have been the single most important question facing a shaken music industry: What is an album in the download era actually worth to fans?

Announced on Monday of last week and then chucked out to rabid fans like flank steak a day ahead of schedule, the band's eighth album dispenses with the honesty-box pricing model but still finds them using their influence to interrogate the terms around how we consume and relate to music. Containing a slight eight tracks across 37 minutes, The King of Limbs is Radiohead's first album to clock in under the 40-minute mark, falling into that limbo between a modern full-length and an EP. What's more, it feels like it stops short intentionally, almost confrontationally, as if Radiohead are trying to ask a new kind of question about their music.

"None of us want to get into that creative hoo-ha of a long-play record again," Thom Yorke told The Believer in August 2009. "It's just become a real drag. It worked with In Rainbows because we had a real fixed idea about where we were going. But we've all said that we can't possibly dive into that again. It'll kill us." This wouldn't be the first time that a member of Radiohead publicly fantasized about disowning the album format, but it might have been the most convincing. How better to unburden themselves of the stress of making more records in the mold of The Bends, OK Computer, Kid A, Amnesiac, and In Rainbows than by simply changing the terms of their engagement?

Radiohead's eighth record, The King of Limbs, represents a marked attempt to create a considered and cohesive unit of music that nonetheless sits somewhere outside of the spectrum of their previous full-length discography. And that's not to say that it doesn't ripple with the dazzling sonics or scenery that have become the band's stock in trade, but just that, unlike so many of their milestones, there's no abiding sense of a band defying all expectations in order to establish new precedents.

Instead, we get eight songs that feel mostly like small but natural evolutions of previously explored directions. Opener "Bloom" announces Radiohead's return with a scattershot sequence of chewed-up drum loops and peeling horns that dissolve into a rhythmic tangle. "Morning Mr. Magpie" re-casts an old live acoustic ballad in a more anxious light, its once-sunny disposition frozen into an icy glare. With its crumbling guitar shapes and clattering, fizzing percussion work, "Little By Little" sounds dilapidated and rundown. Meanwhile, "Feral" contorts Yorke's voice into a reverb-infused, James Blake-like wriggle that pings around the stereo channel against a mulched up drum pattern that sounds sharper than glass.

In this more rhythmic first half of the album, electronic percussion figures in heavily as usual, but also with heightened emphasis on drummer Phil Selway's uneven time signatures. The previously well-rounded band dynamic, meanwhile, feels like it's been reduced to a miniaturized version of itself. This isn't the band that ripped through "Bodysnatchers"; these guys play with a precise, almost scientific restraint that suits the twitchy anxiety of these songs well.

Things open up on the softer, dreamier second side, as rhythms recede and more traditional song structures take over. "Lotus Flower", the lead single presumably for having a chorus and not being a ballad, finds Yorke delivering a series of slippery hooks in slinky falsetto mode. Album highlights "Codex" and "Give Up the Ghost" follow, the former a narcotized cousin to "Pyramid Song" that features woozily flanged piano chords, long, plaintive horn trills, and Yorke at his most evocative; the latter an acoustic, guitar-led call-and-response that finds him piling falsettos into a gorgeously ramshackle wall of harmony. Last is "Separator", a clear-eyed, mid-tempo closer that mixes 1990s–era Radiohead with a touch of Neil Young-inspired guitar work and ends on a sweet and easy note that's miles away from the complicated clatter it began with. Compared to such a dense first half, there's something satisfying about all the open space in the album's final stretch; before you know it, the record's breezed by. It's a nice packing trick, one that makes the album feel even lighter than its 37 minutes.

So: eight tracks, each of them worth your time, and yet The King of Limbs is still likely to go down as Radiohead's most divisive record. A trawl through message boards and social networks leaves the impression that many disappointed fans are still struggling to make sense of the gap between the greatness of the thing they got and the genius of the thing they thought they might get. It's in that gap, when assessing the album overall, that it's easy to get tangled up. This is well-worn terrain for Radiohead, and while it continues to yield rewarding results, the band's signature game-changing ambition is missed.