Last night, Pharrell's G I R L and Rick Ross' Mastermind both hit iTunes as streaming-only releases. What each album represents for its respective artist couldn't be more different. But for each, it's a key release that will prove essential to their careers going forward.

The two albums have taken very different paths: Mastermind followed the old school capital-R "Rollout," and has been months in the making. It included the (somewhat underwhelming) release of Ross' label album Self Made Vol. 3, the release of a single featuring Jay Z ("Devil Is A Lie"), a mini-tour of the U.S. in November, a false release date (in December), a cinematic album trailer set to Curtis Mayfield's "Give Me Your Love," and cover art from Mr. Brainwash.

Pharrell's album, meanwhile, arrived like a happy (no pun intended) accident as conceived on planet web 2.0, as his Despicable Me soundtrack cut "Happy" took off on radio (it's No. 1 on Billboard this week). He dropped "The World's First 24 Hour Music Video" for the song, appeared at the Grammy awards in a big hat, and, post-Beyoncé style, announced an album date just two weeks ahead of time.

Pharrell's G I R L is Cee Lo without the profanity, it's the spirit of OutKast's "Hey Ya," it's the anti-Yeezus, it's Paxil: The Album.

For Pharrell, who just finished a great year with high-profile appearances on the summer's two biggest songs (Robin Thicke's "Blurred Lines" and Daft Punk's "Get Lucky"), it's a chance to prove that he can go it alone—something he's yet to do as a solo artist. (His 2006 album In My Mind was widely seen as, in the parlance of our times, "ehh"). Pharrell's first work came as a producer alongside Chad Hugo in The Neptunes, then as frontman, backed by Chad Hugo and Spymob in N.E.R.D., then as an unsuccessful solo rapper, then as a solo producer for other artists. Although he's been a style icon, a stand-in for the skaters and alt-culture bohemians within and around hip-hop, his efforts as an actual hip-hop star flailed.

What's different for Pharrell in 2014 than in 2006? Although he's still dropping rap verses on other people's songs, G I R L exists, like the pop charts in 2014, as a world without hip-hop. Pharrell has made no other radical changes to Pharrell, songwriter, or Pharrell, cool person. There are as many awkward lyrical moments as any N.E.R.D. album (on "Hunter" he actually sings, "My sex is Kung Fu"). The cheery "Brand New" has the same optimistic innocence of "Things Are Getting Better," one of those songs that ignores complex realities, conflict, gray areas. It is interested in channelling, unobstructed, those momentary flickers of pure happiness, that brief, innocent brain impulse, isolated from pragmatism or complication. It's Cee Lo without the profanity, it's the spirit of OutKast's "Hey Ya," it's the anti-Yeezus, it's Paxil: The Album.

Reaction on Twitter has been uniformly enthusiastic. It's hard to hate "Happy," if not impossible, without seeming like a ruthless contrarian—the song is resolutely un-dislikeable, catchy and memorable, but also clean, without aftertaste. G I R L is designed to soundtrack a hundred family barbecues, to offend no one, to epitomize "good times," and sell massive numbers of copies at Starbucks. For Pharrell to be seen as a true solo star, he needs a hit solo record. He has one.

Meanwhile, Mastermind is an incredibly important record for Rick Ross, but one much more likely to be underrated—and much less likely to succeed. While Pharrell was stumbling with In My Mind in 2006, Rick Ross was just taking off with "Hustlin." In 2013, this dynamic was inverted; Pharrell had one of the best years of his career, and Ross faltered. Despite scoring a guest spot on twin hit records—Rocko's "U.O.E.N.O." and Jay Z's "FuckwitmeyouknowIgotit"—Ross was dumped (in name if not technicality) from his Reebok deal, found little traction on radio for his own material, and failed to release Mastermind by year's end.

For Ross, Mastermind is a test to see if he's still got it. Questions about whether MMG had peaked started to bubble last summer. He had gone from red-hot in early 2012 to rapidly cooling by the following year. It points to the strange, precarious position Ross holds in the industry. On the one hand, aesthetically, he represents a specific vein of hip-hop history: the outsized personalities, the big-budget commercial peak. He also stands as a kind of classicist's ideal of the rap lyricist-as-writer: full of internal rhymes and artful imagery, the contrast between his heavy baritone and the deftness of his bars (at least, since Deeper Than Rap) has given him more longevity than almost anyone expected.

Through a combination of momentum, talent, business acumen, and the ability to sound remarkably like our memories of hip-hop's rapidly dissolving center, Ross' momentum survived, up until the point when the hits stopped coming as easily, the sound shifted slightly.

When he was "exposed" as a corrections officer—always remember, kids, it's not the crime, it's the cover-up—he was presumed doomed; instead, his career was just picking up steam.

Some celebrated Ross' subsequent success as an example of hip-hop finally disposing of its dog-chasing-tail authenticity fetish. Others thought it was a disaster; authenticity had been a checks-and-balances system for ensuring that stars weren't profiting off ghetto stories without some level of accountability. But through a combination of momentum, talent, business acumen—and the ability to sound remarkably like our memories of hip-hop's rapidly dissolving center—Ross survived, up until the point when the hits stopped coming as easily, when the sound shifted slightly. When he's successful, he's easy to root for; this is what big, popular hip-hop is supposed to sound like. When you see him scrambling to keep the tent poles up, or, to mix metaphors, when the seams are showing, it demolishes the illusion.

Mastermind is a good record but also one that is unlikely to halt his gradual slide. More than ever, he plays with our memories of past eras. Even the strong lead single "The Devil Is a Lie" sounds more like the horn-driven hip-hop anthems of the mid-'00s than it does the sound of now. Tracks that liberally flip Biggie and Souls of Mischief (how many times can we sap that loop of its pathos?) suggest less confidence in Ross' ability to stay relevant. Mastermind still cultivates, in its best moments, the smooth grandeur of Deeper Than Rap-era Ross, rather than the aggressive club bangers of the "B.M.F." era. Songs like "Rich Is Gangsta," "Supreme," "Blessing In Disguise," and "Paradise Lost" are undeniable moments of hip-hop muscle, confident assertions of hip-hop's vitality in an era when the center has moved further from the genre than ever before. But it's not likely that this album will stop that process.

David Drake is a Staff Writer for Complex. He had his picture taken with Mya yesterday. You can follow him on Twitter at @somanyshrimp.

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