Editor's note: Mark Yarm is the author of "Everybody Loves Our Town: An Oral History of Grunge."
(CNN) -- During the days leading up to the 20th anniversary of the release of Nirvana's landmark album "Nevermind" on Saturday and the grunge album's deluxe reissue the following Tuesday, you're going to hear a lot about how "Nevermind" changed everything:
How the band's single, "Smells Like Teen Spirit," was a phenomenal, seemingly overnight success that ushered so-called alternative rock into the mainstream.
How the success of "Nevermind" ignited a major-label feeding frenzy to find "the next Nirvana," resulting in the signing of previously way-too-weird-for-a-major-label bands such as underground heroes The Jesus Lizard and Japanese noise-rockers the Boredoms.
How most of these groups were unceremoniously dropped when they didn't sell boatloads of records, while groups perceived by many to be Nirvana and/or Pearl Jam ripoffs (i.e.: Stone Temple Pilots, Candlebox, Bush) achieved multiplatinum success.
How Kurt Cobain gave voice to a disaffected, flannel-clad Generation X. And how Cobain was a musical genius, gone from this Earth too soon.
And all of these things are true, aside from the hair-metal myth (glam-metal was already a genre in decline by that point).
You'll also be hearing a lot of use of the word "grunge," a label used -- typically to the labeled party's chagrin -- to describe purveyors of the raw fusion of heavy metal and punk rock that emerged from the Pacific Northwest. But what you won't hear quite so much are the specifics of that emergence. In some quarters, it seems 1991, which also saw the release of Pearl Jam's multiplatinum debut album "Ten" and Soundgarden's "Badmotorfinger," is being treated as year 0 of grunge, because that's when the music exploded into the mainstream consciousness.
In fact, grunge's roots can be traced back to the 1980s, if not further.
"Deep Six," the 1986 compilation on Seattle label C/Z Records, is recognized as the first record to document this burgeoning regional sound. It featured a half-dozen local bands: Soundgarden, Green River, the Melvins, Malfunkshun, the U-Men and Skin Yard.
None of those groups is a household name, save for Soundgarden, which scored a No. 1 hit with the album "Superunknown" in 1994 and just this year embarked on a North American reunion tour after more than a decade apart.
But if you want to know how Nirvana and Pearl Jam came to be, these six bands -- whose histories are tightly intertwined -- are a good place to start.
Skin Yard's guitarist, Jack Endino, produced Nirvana's the down-tuned and scuzzy debut album, "Bleach." Members of Green River, often cited as the first grunge band, went on to form Pearl Jam and quintessential grunge rockers Mudhoney.
The Melvins, who have essentially never stopped touring or recording with 20 studio albums to their name, were friends and mentors to Nirvana's Cobain and Krist Novoselic, who hailed from the same rural part of Washington state. As Novoselic once said of the sway Melvins frontman Buzz Osborne held over him: "Buzz was the preacher, and his gospel was punk rock." The Melvins sonic influence on Nirvana's first album is unmistakable.
But to hear Osborne tell it, his band's importance has too often been diminished.
"All (Nirvana) biographers want to do is pretend that we don't matter," the never-shy singer/guitarist said to me at the onset of the first interview I conducted with him for my book. "They talk us down like none of this makes any difference, but what they have to understand, and what needs to be clearly stated, is that without us, there is no Nirvana. Without us, there is no Nirvana."
So by all means go ahead and purchase the "Nevermind" reissue or catch a showing of Cameron Crowe's new "Pearl Jam Twenty" documentary, and relive the glories of grunge's most commercial era.
But if you want a deeper understanding of where grunge came from, investigate some music by the Melvins (those Nirvana biographers be damned!) or Mudhoney or any number of other grunge bands not fronted by someone with the surname Cobain, Vedder or Cornell.
Yes, 1991 was a very good year for grunge, but why not try something of a different vintage?