It's a small square box that flips open, and inside are 11 CDs, two of them two-record sets, all of them making up the complete studio collection of Byrds albums. All of them. Every studio recording the Byrds made. And with this set in hand, we can finally see exactly how important the Byrds were to American music. By listening to their entire recorded output from beginning to end, we can get a complete sense of who these guys were and what a tremendous gift they gave us.

It's worth noting that each album has been remastered and contains bonus material -- outtakes, alternate takes, songs edited off the final albums and so on. With Sweethearts of the Rodeo, for example, we get not only the original album but the alternate takes with Gram Parsons singing lead on songs that were released on the album with McGuinn's lead vocals. We also get a few cuts of Parsons' Original Submarine Band doing material that wound up being re-recorded for the Sweethearts album.

The point is, when Sony says "complete," they aren't joking.

So, what did the Byrds give us and exactly how important were they? The most obvious way they've influenced other musicians and still continue to is the use of Roger McGuinn's jingle-jangle guitar, a Rickenbacker 12-string. You can hear echoes of his playing in almost every folk, pop or rock record released. It's almost the basic lick of Americana music.

But you can also see how much of the Byrds were Roger McGuinn. One of the founding members of the group, he was the only one who was there the whole way, from start to finish. The band's vision was actually McGuinn's vision.

It's important to remember that the Byrds came out of folk music. McGuinn was the banjo and guitar accompanist for both the Limelighters and the Chad Mitchell Trio before serving a stretch as Judy Collins musical director. David Crosby was a coffeehouse minstrel for years. Not to Brian Williams you, but I knew him slightly when he was working the Flick and other South Florida coffeehouses a couple of years before the Byrds, before he went home to LA to join the Les Baxter Balladeers. Gene Clark came out of the New Christy Minstrels, while Chris Hillman was a bluegrass player.

By the time they became the Byrds, they had added rock to their bag of tricks, but the records show they never went far beyond folk. You can make a case that they were always folkies, but with an additional kicker: they were musicians -- skilled, knowledgeable, talented and, like most musicians, restless, always hungry to create.

Listening to these 11 albums in order, from first to last, you recognize a progression, a continued deepening as more and more influences come into their writing and playing. The famous "Eight Miles High," for example, is based on the chord progression the jazz master John Coltrane used in his take on "My Favorite Things."

You can also make the case that each album is, in fact, an experiment, seemingly born out of a desire not to repeat themselves, to continue to stretch themselves artistically. The first one, Mr. Tambourine Man, invented folk-rock, mostly by amplifying Bob Dylan and Pete Seeger tunes and writing modern songs using folk themes. McGuinn's guitar parts -- he was the only member of the band allowed to play on that first album -- are made up of the same techniques he used as a folksinger, just pushed through an amplifier.

The followup, Turn, Turn, Turn, indicates its direction by using a Pete Seeger song as its title track. It's a full-bore folk music album, whose musical statement appears to be, "the record company wouldn't let us all play on our first album, so let us show you what we can do with the same sort of material those studio guys played last time."

Having made the statement, the Byrds' restlessness surfaces and they next record Fifth Dimension, introducing space-rock to their repertoire. Many of the songs are rooted in science fiction -- "5D," "Mr. Spaceman," "The Lear Jet Song" among them. These are anchored by traditional folk songs -- "Wild Mountain Thyme," "John Riley." It's as though McGuinn and company want to show us the connection between past and future.

And so it goes. Sweethearts of the Rodeo invents country rock, The Notorious Byrd Brothers is their psychedelic album, each new album goes in a different direction, and since by now the Byrds' lineup changes are as legendary as their songs, we might say that each album goes in whatever direction Roger McGuinn is interested in. It has been said that McGuinn could take any three players and turn them into Byrds, and that's true up to a point.

As long as he was willing to remain autocratic, to be the benevolent dictator of the band, then any group of Byrds he fronted made fine music. In the later days, though, he became sensitive to the dictator charges and made the creative mistake of letting the other musicians contribute more. Since they sometimes did not share his vision, a couple of the later albums get muddy as the Byrds records become more of a product -- the very plastic wares they complained about earlier -- and less of a driving force. The records are still strong but are not as tightly focused as they were before.

But then Clarence White comes into the band. White, one of the great bluegrass guitarists and session musicians, was a master guitarist and singer whose vision matched McGuinn's perfectly and who was just the guy to join McGuinn in going where he wanted to go: deeper into country-rock, folk music and bluegrass.

Playing and singing alongside White, McGuinn sounds renewed, completely reinvigorated, as though he is once again in it for the music. Together, acoustically or electronically, the two guitars are amazing, playing off of each other, feeding and challenging each other. Untitled, Unreleased, a two-record set, presents them in both a studio and live setting and the live sides are unbelievable, filled with just wonderfully joyful singing and playing. McGuinn sounds relaxed and happy in this setting, with which he toured and recorded until Clarence White was hit by a car while loading gear into his van and died.

With White's death, McGuinn decided to hang up the Byrds and go on to a solo career that he still enjoys, continuing to perform worldwide.

This set of albums is his legacy and what it shows is that the Byrds, successful and respected as they were, never fully got their due. For all their success and critical acclaim, the band was never recognized as what it was: one of the most creative, imaginative and very best bands America ever produced.

This set corrects that oversight.