Humbug has long been Arctic Monkeys' most underrated album, and it's also one of the most important and necessary albums of their career, if not the most important and necessary. A few years earlier, Arctic Monkeys emerged as a Strokes-obsessed, charmingly sloppy, absurdly buzzed-about British garage rock band who took the world by storm with 2006's Whatever People Say I Am, That's What I'm Not. They followed that album just a year and a quarter later with Favourite Worst Nightmare, which saw them tightening up, playing faster than ever, and coming out with more instantly-beloved songs. Now, when you think about the band's "early" or even "classic" era, you are probably thinking about those first two albums. For a while, the songs from those albums were really the only Arctic Monkeys songs to leave a visible impact on mainstream music (at least in the US). That is, until 2013's AM, which saw the Arctic Monkeys delivering slicked-up stoner metal riffs over hip hop beats and coming out with major singles like "Do I Wanna Know?" and "Why'd You Only Call Me When You're High?" that sounded equally at home on classic rock radio as they did on modern pop radio. For a while, the consensus was generally that the band's debut was their magnum opus, but now there's just as many or more people who would say AM is. When Arctic Monkeys changed up their style yet again for 2018's Tranquility Base Hotel & Casino, it went over much better than the first time Arctic Monkeys made a drastic stylistic change, because fans and critics knew to expect it from them at this point. The Arctic Monkeys are far removed from the days of being a garage rock buzz band, and they've left the large majority of their garage rock buzz band peers in the dust. And the album that made it all possible was 2009's initially-divisive Humbug, which turns 10 today.

The band's first two albums are stone-cold classics, so what I'm about to say is in no way a slight to those albums, but Humbug proved Arctic Monkeys could successfully be a versatile band, one who would become more known for longevity and for constant reinvention than one known for a buzzy album at the height of indie-mania. When they started out, they had a reputation as a band who was loud, fast, and spontaneous. On Humbug, they slowed down. They took more time to make the album, the tempos were slower, and the songwriting was more measured. They were no longer pulling mostly from rowdy garage rock, but from tripped-out psychedelia, lumbering doom metal, hypnotic stoner rock, and darker songwriters like Nick Cave (whose "Red Right Hand" they covered as a bonus track for the album). Comparisons were made not to The Strokes but to Black Sabbath and Queens of the Stone Age (whose Josh Homme co-produced the album), and not everybody was happy about it. The AV Club gave Humbug a C+ and called it "significantly less memorable" than its predecessors. SPIN gave it a 6/10 and said there's an "almost suffocating tonality to the songs... it's accomplished, but not particularly infectious," later adding, "Stay tuned for their back-to-basics fourth album." (Never happened!) Even the Arctic Monkeys-loving NME only awarded it a 7/10, following the 10/10 they gave the debut and the 9/10 they gave the sophomore LP, and they wrote "the people who kinda liked ’em will be wondering who the fuck they are in five years’ time." In actuality, they made the gigantic AM in four years' time and it became the second time NME gave the Arctic Monkeys a 10/10.

The Arctic Monkeys stuck to their guns and proved the naysayers wrong. They further honed the heavier, more psychedelic side of their sound with 2011's Suck It And See and they perfected it with the hugely popular AM. I'd probably call AM their best album at this point, but there's always something special about the first time a band stumbles upon a new idea. The Beatles made highly-celebrated psych-pop classics with Revolver and Sgt. Pepper's, but it also always remains a unique thrill to hear them first figuring out psychedelia with earlier songs like "Norwegian Wood." Likewise, it's a thrill to hear how Humbug laid the blueprint for AM. Humbug is also a thrill because the Arctic Monkeys never really made an album like it before or since. They had other heavy psych songs on Suck It And See (like "Don't Sit Down 'Cause I've Moved Your Chair" and "Library Pictures") but that album leaned more heavily on the band's love of tender ballads. AM still paid total homage to Sabbath and QOTSA but it was much more of a modern-sounding pop record than Humbug. Humbug remains the band's all-around heaviest, darkest, and nastiest album. Like many bands who evolve again and again, even the seeds for Humbug were being sewn on earlier albums. Take the darker guitar riffs of "The View From The Afternoon" or "Still Take You Home" or "Brianstorm" or "Teddy Picker" from the first two albums and slow them down a bit, and you'd be left with something that resembles the turn Arctic Monkeys took on Humbug. So the sound of Humbug was always brewing inside the Arctic Monkeys; the band's trip to the desert with Josh Homme just fully coaxed it out of them.

Humbug is at its heaviest on penultimate track "Pretty Visitors," which starts out as the album's fastest, most punk-inspired song but turns into a dose of doom metal so punishing that even doom master Tony Iommi might be wishing he thought of it first. (I'm not sure what Iommi actually thinks of the band, but for what it's worth, Lars Ulrich is a huge fan.) "Pretty Visitors" (thankfully) remains a staple of the band's live show today, along with the gorgeous, lyrically vivid ballad "Cornerstone" and the album's upbeat, ease-them-in-to-the-new-sound lead single "Crying Lightning," but Humbug has so much more to offer than those three songs. Album opener "My Propeller" remains one of the most addictive and most unique songs in the band's catalog. It's -- cheesy pun alert -- propelled by drummer Matt Helders, who knows how to write wildly complex parts that don't take away from Alex Turner's ability to write catchy pop songs, and it's one of those songs where Helders' beats are as memorable as Turner's words. It's dark and creepy, qualifiable as "desert rock" but more Nick Cave than Queens of the Stone Age, and it's a tension-building song that saves its best hook for last. "My propeller won't spin and I can't get it started on my own / When are you arriving?," Turner sings on repeat, changing it slightly each time, with the end of one line blurring into the start of the next like an actual propeller spinning infinitely. It's trippy and entrancing, yet -- in its own way -- as catchy as the band's biggest hits.

"Potion Approaching" arguably had even more hit potential than "Crying Lightning," with a choppy main guitar riff that sounded more like Favourite Worst Nightmare than Humbug tends to, a slowed-down, eerily acid-drenched chorus with more memorable pounding from Helders, and an even more slowed-down bridge that dives even further into trippy desert rock territory than most QOTSA songs. It strikes a fine balance between the Arctic Monkeys' pop sensibilities and their more experimental tendencies, and it's a true shame that it's one of the band's lesser-performed songs. "Dangerous Animals" is another could've-been hit, with its groovy rhythm section and another strangely addictive chorus that's up there with any of Alex Turner's best tongue twisters. (Everyone loves a good word-spelling lyric, and even though I know how to spell "A-N-I-M-A-L" and "D-A-N-G-E-R-O-U-S," Turner's pacing always throws me for a loop.) And while Humbug's reputation often concerns its knack for metal riffage or its tricky rhythm section, the album also offers lava lamp-conducive, dazed and confused balladry like "Fire and the Thud" and "Dance Little Liar," and songs that bounce back and forth between the busy-sounding stuff and the hazy stuff like "Secret Door." Arctic Monkeys have gotten weird on every album since Humbug -- and their latest Tranquility Base Hotel & Casino proves they are definitely not done getting weird -- but Humbug is the one that's most consistently loaded with this kind of stuff. Outside of "Cornerstone" (which, again, is a gorgeous song), there isn't a song on Humbug that doesn't sound like it could be set to the peyote scene from The Doors' movie. They learned how to keep their pop songwriting intact while experimenting with all kinds of psychedelic sound effects, and Humbug remains not just a pivotal moment for Arctic Monkeys' career, but one of the only times in the past decade that a rock band this popular made an album this unexpected.