Has it really been 20 years since Nirvana's 'Nevermind' was unleashed upon the world? It’s long been considered an album that defined a generation, spawned a musical movement and, well, f---ing rocked. But was it really that revolutionary, or was it a pretty damn good album that just happened to be at the right place at the right time?

The cultural significance of the album can (and will) be argued over endlessly for generations to come, and the 20th anniversary editions of ‘Nevermind’ that dropped this week will do little to resolve that debate. But as a historical document, the sets offer an unparalleled look into the creative process that went into the making of Nirvana’s magnum opus.

The 20th anniversary ‘Nevermind’ comes in several different packages, including the recently released two-disc deluxe version (reviewed here) and the four CD/one DVD super deluxe collector’s edition, which comes out Oct. 24 and retails for $179.99 (but can be found for a bit less at select outlets). Obviously not intended for the casual fan, the super-deluxe set delves deep into the Nirvana archives, offering unfettered access to a ton of Nirvana demos, B-sides, rarities, outtakes and live recordings.

Starting with disc one of the deluxe version, you’ll get the complete ‘Nevermind’ album, remastered specifically for this release, plus the 10 B-sides that originally came with each ‘Nevermind’ single release (‘Smells Like Teen Spirit,’ ‘Come as You Are,’ ‘In Bloom’ and ‘Lithium’). What’s the difference between the 1991 ‘Nevermind’ and this remastered version? It’s hard to pin down, although listen closely enough and some contrasts do come out. The B-sides include rare Nirvana classics like ‘Curmudgeon,’ ‘Sliver’ and a cover of the Wipers’ ‘D-7’ recorded at the BBC.

Disc two offers 18 tracks including the famed Smart Sessions (pre-‘Nevermind’ demos recorded at Butch Vig’s Smart Studios in Wisconsin), Boombox rehearsal tapes (Nirvana’s lo-fi home recordings as they constantly rehearsed) and several BBC radio appearances. The key here is ‘Sappy,’ a song that turned up as the hidden track on the 1993’s ‘No Alternative’ charity compilation (it was known as ‘Verse Chorus Verse’ back then). That version was a bit grittier than the one here, which gets the glossy ‘Nevermind’ treatment.

The aforementioned super-deluxe edition, which we'll review around its release date, features the two discs included in the deluxe version, as well as two additional CDs and a DVD. Disc Three consists of ‘Nevermind’ producer Vig’s original mixes of the album (called the Devonshire Mixes). Disc Four and the additional DVD include the audio and video, respectively, of the complete ‘Nirvana: Live at the Paramount’ concert, the previously unreleased document of the band’s 19-song Halloween night 1991 performance in their hometown of Seattle.

20 Things You Didn't Know About Nirvana's Nevermind


Nirvana 'Nevermind' Giveaway

Enter your e-mail address for a chance to win one of 10 Nirvana 'Nevermind' Deluxe Edition CDs courtesy of Universal Music Enterprises, Loudwire.com and UltimateClassicRock.com. Contest ends Oct. 24. Click here for official rules.