Their first record was called Whatever People Say I Am, That's What I'm Not-- a Nevermind the Bollocks-type sendup of the generation-defining Self-Titled Debut Album as well as a bratty act of defiance from four Yorkshire youths drunk on their own twitchy cleverness. Their fifth album is called AM, and those mountainous initials stood sky-high behind the band as they preened and stomped like proper rock stars through a headlining Glastonbury set earlier this year. Their face-shrouding hair and brown hoodies are out; greaser streaks and bespoke suits are in. And the same band that once aimed its sights at windbag poseurs on "Fake Tales of San Francisco" is now based in Los Angeles. These changes have caused some to question Arctic Monkeys' commitment to their initial no-bullshit ideals. But the quartet isn't giving into the mindless grandeur of rock'n'roll as much as they're working within its confines to mine new territory; over the last eight years, as they've gone from spastic punk, to doomed stoner rock, to sparkling guitar pop, to this new album's skinny-jeaned funk, Arctic Monkeys have stayed close to the spirit of their debut's title while minimizing its excess at the same time.

Meanwhile, singer and lyricist Alex Turner has moved from syllable-stuffing chronicles of indie nightlife culture to songs that are sleeker, more blue-black, more self-lacerating. Thematically, AM centerpiece "No. 1 Party Anthem" comes off like a seedier take on Arctic Monkeys' breakout track "I Bet You Look Good on the Dancefloor" as it tells of a collar-popped lothario on the prowl in a dank club made up of "lights on the floors and sweat on the walls, cages and poles." But instead of blaring, this anthem is wistful, its piano, acoustic strums, and croons suggesting days gone by (along with 70s Elton John and Rod Stewart). Its swirling bridge sums up the scene in just a few choice phrases-- "The look of love/ The rush of blood/ The 'she’s with me'/ The Gallic shrug"-- and sounds like a definitive endnote to Turner's most notable songwriting style.

So AM goes beyond the sweaty clubs and furtive flirts into the hotel rooms, after parties, and bad decisions that can follow. The crux of the record is neatly summed up by the hook to the blistering "R U Mine?": "R U mine tomorrow, or just mine tonight?"-- an entire world of sex and love and desire distilled to quick-hit text-speak that Drake could appreciate. Turner isn't sure of the answer to that question, and the resulting limbo does his head in all over the LP. He's an avowed romantic living in an unromantic world, grasping for meaning in a city-to-city road-dog lifestyle hellbent on repelling it. In some ways, Turner's struggle and his band's recent gleaming transformation into something like rock gods is reminiscent of U2's turnaround circa Achtung Baby, when that quartet traded in deep virtuousness for sin, rhythm, and leather jackets. For Arctic Monkeys, loosening the tether to credulity can be freeing, allowing the band to live out their classic-rock dreams: T. Rex bop, Bee Gees backup vocals, Rolling Stones R&B, and Black Sabbath monster riffage are all rendered modern throughout AM with the help of longtime producer James Ford. And for Turner in particular, the switch has him connecting strings of desperate 3 a.m. thoughts: some horny, some bleary, some a bit frightening.

Two of the album's slinkiest and best tracks have Turner sounding slyly wolfish, like a perplexed predator confusing lust and longing. "I dreamt about you nearly every night this week," he purrs on opener "Do I Wanna Know?", which slowly rolls forward thanks to guitarist Jamie Cook's lizard-brain riff and drummer Matt Helders' Queen-sized beat; "Knee Socks", meanwhile, tells of a wintertime tryst that climaxes with an operatic guest vocal from Queens of the Stone Age's Josh Homme, who could've used some of AM's groove on this year's lumbering … Like Clockwork. Whereas 2009's Homme-produced Humbug had the Arctic Monkeys trying on QOTSA's heaviness with varied success, AM integrates its influences more fully-- and, at times, even beats Homme at his own snake-rock game.

The only solace found on this paranoid and haunted album is within its eclectic music, as well as the idea of music itself. "Mad Sounds" is AM's most hopeful song, an achingly sincere ballad that employs melody, swing, and "oh la la las" to attest to the power of melody, swing, and "oh la la las." It teases out the purest interpretation of the Rorschach-like sine waves that adorn AM's cover, which-- depending on your vantage, or mood-- could also read as leering sunglasses or maybe a bikini top. Creeping closer "I Wanna Be Yours" combines all three meanings while seemingly answering the question posed by opener "Do I Wanna Know?" That is: When faced with the choice between easy pleasures and lasting devotion, Turner is picking the latter. Sweet, right? But upon further inspection, it's not so simple. "I Wanna Be Yours" features lyrics by UK punk poet John Cooper Clarke from his 1982 track of the same name, which uses the language of commercialism to express the deepest love. "I wanna be your vacuum cleaner, breathing in your dust," sings Turner as a lonely drum machine highlights the sentiment's emptiness. Still, the song doesn't sound cynical. It's genuinely affecting. The ultimate message-- will future generations have the capacity to love people as much as their cars, their coffee pots, their phones?-- rings terrifyingly true in our time of personal branding. Arctic Monkeys let these thoughts languish. "Maybe I just wanna be yours," Turner sings. Maybe not.