Among the most significant and welcome folk-roots releases of the year, the three-disc Legacy surveys the career of Dave Ray (1943-2002), who in a just world -- in other words, not this one -- would be a whole lot more famous than he is. In common with other hugely talented, largely unheralded musical figures, Ray is more influential than well known.

He is most recognized as a member of the folk-blues trio Koerner, Ray & Glover, formed in the Twin Cities in 1962. Their 1963-1965 Elektra recordings -- on which, oddly, the three seldom perform as a unit on any individual cut -- are sometimes singled out for grand praise by rock stars past and present. (I detest the insulting and patronizing notion that musicians are validated only when endorsed by more prominent, financially rewarded performers. If you're interested in who Ray's celebrity fans are, you can look up the names.) These albums remain in print, thanks to Red House reissues a few years ago. The three men later cut records, on Elektra and elsewhere, featuring various permeations of the "band," a noun used loosely in this context. On their own blues harpist Tony Glover and (notoriously eccentric) trad-folksinger Spider John Koerner continue as active performers.

Though the three took all but perverse pride in living separate lives off stage (refusing even to rehearse together), at gigs and in recording studios Glover usually accompanied Ray, a blues singer and guitarist who would on occasion stray into rock and r&b. The current project owes to Glover's committed efforts, supported by Red House head Eric Peltoniemi, an old friend of mine and, like me, a longtime Ray (and Glover and Koerner) fan. If you already know Ray's music, you'll want this exemplary set, and if you don't know it, it's your chance to pick up on someone unique and memorable.

The three discs that comprise Legacy are, as the subtitle explains, "Rare & Unreleased Recordings 1962-2002," presented in essentially chronological order. In common with other white blues players from the 1960s revival, Ray was introduced to African-American folk music through Lead Belly's recordings. On the Elektra albums Ray offers up some sterling arrangements of Lead Belly songs (who can forget his version of "Titanic"?), but two on the first Legacy disc -- "Fannin Street" and "Frankie & Albert" (the latter 10 minutes' worth, yet) -- are of no more than historical interest. (Glover's liner notes bluntly acknowledge that Ray probably wouldn't have wanted these resurrected.) But other numbers inform us how good Ray was early on, a middle-class Minneapolis kid who had a natural feeling for blues and other black roots music. Here he recreates, without redundancy, songs by Leroy Carr, Skip James, Muddy Waters and others, as well as a couple of in-the-tradition originals. I am particularly enamored of the hard-traveled reading of Brownie McGhee's "Lonesome Road," a different take from the one that appears on 1965's Return of Koerner, Ray & Glover.

Disc Two covers 1988-1994, a period when Ray was no longer working as a full-time musician but still performing whenever opportunity presented itself, recording occasionally on small labels with Glover or with other associates. Most of all, while he delved ever more deeply into (mostly) country blues, he was always sharpening his craft, evolving from already accomplished to fully mature. Disc Three (1995-2002) exposes his growing interest in jazz; not that he was reinventing himself as a jazzman, but he was learning how to incorporate jazz elements into downhome blues. There are some charming oddities: a commercial for a Twin Cities radio station, the Richard Sherman-penned Disney tune "Trust in Me" and Bill Monroe's "With Body & Soul." But it's the opening cut, Ray's moving inhabitation of the traditional "Shake 'Em on Down," that evinces the truly one-of-a-kind interpreter he had become as the blues traveler neared the end of the lonesome road. He died of cancer on Thanksgiving Day 2002.

Dave Ray will remind you of nobody. His vocals are so distinctive as to be instantly recognizable, his playing rhythmic and affecting. Ray at peak performance will not soon leave you. From the first he possessed an almost instinctive understanding of a music he had not grown up with, but only stumbled into in his teens, never to let go. It all goes to, perhaps, the mystery and miracle of genius. Whatever it is, it makes Ray an unlikely hero of the blues and Legacy a treasure to be returned to again and again.