The annals of contemporary music are rife with legendary unreleased albums: the Beach Boys’ “Smile,” The Who’s “Rock Is Dead,” Marvin Gaye’s “Love Man,” David Bowie’s soundtrack for “The Man Who Fell to Earth,” several from Prince, Bruce Springsteen and perhaps most of all, Neil Young. Usually, such albums turn out to be unfinished and overblown in terms of their significance, leaving die-hard fans trying to piece together the ultimate version of a tantalizing missing link in a beloved artist’s catalog from scraps that were never a whole in the first place (or, in the case of “Smile,” a sprawling 9-CD boxed set from the unfinished album’s sessions).

That is definitely not the situation with Neil Young’s 45-year-old new album, “Homegrown,” a rare missing link that actually lives up to its legend. Not only does it fill a logical gap in Young’s catalog, it’s one of the best albums from his 1970s golden era, one of the great creative hot streaks in contemporary music. The opening track alone, “Separate Ways,” which is more than a little reminiscent of Young’s classic “Heart of Gold” (and which was released in a different version recorded in the early ‘90s), will have any serious fan thumping their head, incredulous and almost angry that he sat on this album for so long.

It seems that even the mercurial and legendarily contrarian man himself doesn’t understand why he didn’t release the album — which he describes as the “unheard bridge” between two acoustic-based albums, the 1972 classic “Harvest” and 1978’s “Comes a Time” — in the first place.

“I apologize. This album ‘Homegrown’ should have been there for you a couple of years after ‘Harvest,’” he wrote on his Archives website announcing the album’s release. “It’s the sad side of a love affair. The damage done. The heartache. I just couldn’t listen to it. I wanted to move on. So I kept it to myself, hidden away in the vault, on the shelf, in the back of my mind….but I should have shared it. It’s actually beautiful. That’s why I made it in the first place. Sometimes life hurts. You know what I mean.”

There you have it.

Originally scheduled for release in 1975, “Homegrown” actually makes a lot more sense in Young’s chronology than “Tonight’s the Night,” the dark and harrowing album he decided to release in its place. It’s sun-baked and acoustic, paradoxically reflecting both the emotional intensity (the breakup of his relationship with actor Carrie Snodgress is the heartache in question) and laid-back grooves of the stellar album that preceded it, 1974’s “On the Beach.” There are a lot of acoustic guitars and mid-tempo songs; the presence of The Band’s drummer Levon Helm on two songs adds to the slightly ramshackle feel, while Emmylou Harris’ backing vocals bring a country vibe to two others. The similarities to “Harvest” and “Comes a Time” are emphasized by the presence of Young vets like bassist Tim Drummond and pedal steel guitarist Ben Keith.

It’s a fully realized, well-sequenced album too — not a collection of outtakes — and while several of the 12 songs have been released over the years (see Rolling Stone for a forensic track-by-track guide), there’s little question that they make much more sense here. Along with ballads and loose rockers, there’s a bizarre spoken-word piece called “Florida” (the lyrics to which, true to Young’s self-referential nature, appeared on a poster that came with “Tonight’s the Night”), a “Rainy Day Women”-style stoner raveup called “We Don’t Smoke It No More,” and several stellar songs ranging from the keening “Star of Bethlehem” to the rocker “Vacancy,” some of which are familiar, some not.

In case it wasn’t already obvious, “Homegrown” is an essential addition to the Young catalog and the best of his many archival releases since the equally essential “Live at the Fillmore East” (which was recorded in 1970 and finally released 36 years later). And while this OCD-level self-archivist has been dropping both new and old material at a furious clip, there’s still plenty in his vast, six-decade archive — hey Neil, how about the unreleased 1977 album “Chrome Dreams” next?