You are probably aware that the Beatles were a great rock band. What you might not know is that they were also a band that rocked.

Yes, for whatever reason -- maybe it was John Lennon's glasses? -- the Beatles have always sort of been viewed as artistes by the majority of critics (and probably fans too), a studio band that studied transcendental meditation and wrote songs about an "Octopus's Garden" (to say nothing of sound collages like "Revolution 9"). A large portion of the blame for this probably lies with the Beatles themselves, who, by the mid-'60s, were seemingly doing everything in their power to make their mop-top past a distant memory. They grew their hair long, experimented with LSD, wrote tunes like "Norwegian Wood" and "Tomorrow Never Knows" and famously -- and disastrously -- declared themselves to be "bigger than Jesus." This is the kind of stuff rock-and-roll parodies are made of, after all.

But it was during this period of experimentation and reinvention (which, generally speaking, began with 1965's Rubber Soul and ran until their final album, 1970's Let It Be) that the Beatles also became a true rock act, a band as adept at creating sexy, swaggering skronk like "Savoy Truffle" and ballsy, barroom bop like "Hey Bulldog" as they were doomy, blistering cacophony -- check the last two minutes of "I Want You (She's So Heavy)" -- and even, as some have posited, proto-metal, in the form of "Helter Skelter," which pre-dates hard-rock deities like Black Sabbath and Led Zeppelin by roughly a year.

And yet, the Beatles are rarely acknowledged for any of this -- and not just because folks wanted to focus on their facial hair (which, admittedly, was pretty excellent at the time). Rather, it was because their brand of rock covered so many corners that it practically defied categorization. The Beatles were never as leaden as Zeppelin, as swaggering as the Stones, or as sludgy as Sabbath; they were all of those things and then some. And because of that, their influence not only extends well beyond arbitrary musical borders but decades too. In fact, you can hear it today in everything from the Foo Fighters' arena-uniting, radio-friendly bombast and Foster the People's hazy, gauzy pop to the Arcade Fire's earnest, epic scope and the Killers' starry ballads (to name just a few).

So it's fitting that, finally, the Beatles' best rockers are getting their due, in a new iTunes comp called [article id="1690398"]Tomorrow Never Knows.[/article] Over the course of 14 tracks, it valiantly attempts to chart the band's journey through rock, grouping FM-friendly numbers like "And Your Bird Can Sing" and "Paperback Writer" alongside frantic, rhythm and blues workouts like "I'm Down" and strutting stompers like "Back in the U.S.S.R." Favorites like the fuzzy "Revolution" and the widescreen "She Said She Said" make the cut (of course), but the album also wisely includes heavy nuggs like the aforementioned "Helter Skelter" and the head-spinning title track "Tomorrow Never Knows," a song so multilayered that its mere creation in 1966 -- on tape loops, nonetheless -- seems practically unimaginable, and its prescience seems downright eerie (no matter what Don Draper thinks).

It's by no means a perfect cross-section of the Beatles' body of rock (any Beatles fan can probably put together a list of tracks they would have added; mine would include "She's So Heavy," George Harrison's "While My Guitar Gently Weeps" or even "Happiness Is a Warm Gun"), but it takes on a near-impossible task -- attempting to sum up the greatest band of all time's most feverishly creative era -- and does the job admirably, showcasing a side of the band that most were aware of yet few truly appreciate.

Tellingly, the album's release is also accompanied by love letters penned by the likes of the Foos' Dave Grohl (who extolls the virtue of "Hey Bulldog" and lets it be known that "If it weren't for the Beatles, I would not be a musician") and Maroon 5's Adam Levine, all of which speaks to the band's influence, regardless of genre. It's just another example of how great the Beatles really were, even if we probably don't need another example of that greatness. To be certain, they always rocked -- even back when they were covering "Twist and Shout" -- but rarely have fans been given an opportunity to experience just how influential (and wide-spanning) their rock really was. It's something that's almost impossible to sum up and, as Tomorrow Never Knows proves, equally impossible to sell short.