David Freeman, who grew up in New York City in the 1950s, first heard traditional Southern music on the radio while on an automobile trip to New Orleans with his parents. The sounds dazzled and haunted him, and in pursuit of them he eventually moved to Virginia. In the 1960s he founded County Records to document mountain ballads, songs and tunes in all their variety. Some releases (in the 500 series) were devoted to commercial hillbilly recordings from the 1920s and '30s. Many of us learned of Charlie Poole, Burnett & Rutherford, Clarence Ashley, Uncle Dave Macon and more from those anthologies, which decades later constitute the gold standard.

Even more remarkably, for County's 700 series (the basis of the four-disc retrospective up for review), Freeman and associates Charlie Faurot and Rich Nevins took to the field to record active rural musicians along the border of southwest Virginia and northwest North Carolina. Old-time was still a lively, vital presence in a musical culture that retained a surprising purity, intact and untouched by contemporary commercial country music. There were bluegrass bands, and some very good ones (e.g., Larry Richardson's legendary outfit), but banjo and fiddle, sometimes guitar and mandolin, played the old-fashioned way could be heard just about anywhere.

A number of the players whom the three initially encountered were regulars at a well-known local festival, the Old Fiddlers' Convention, at Galax, Virginia. From there, through tips and other leads, they met, for one example, Virgil Anderson who lived in a remote cabin, according to Legends of Old-Time Music's excellent liner booklet, "accessible only by a narrow swinging bridge stretched across the Little South Fork of the Cumberland River that butts the Cumberland Plateau." Defying a host of urban stereotypes, Anderson, his wife and son proved warm and welcoming. It turned out, moreover, that he and a local musical family, the Bertrams, were close friends and mutual influences. Because the Bertrams were African American, Anderson's music encompassed the rural traditions of more than just the white South.

The riches are here in such overwhelming abundance that Anderson gets only three cuts (including the bluesy "You Been Gone So Long") of the 113 comprising Legends of Old-Time Music. (As the late Mike Seeger quipped, "'Old-time' is what the folk call folk music.") It's one memorable performance after another, and the trio of collectors deserves full credit for taking care to draw the very best out of the artists. As they make this point, the notes recount Nevins and Faurot's frustrating, week-long effort to secure a definitive reading of "When Sorrows Encompass Me 'Round" from the late Tommy Jarrell, a North Carolina banjoist and fiddler revered by those who care about Appalachian music. Finally, the sudden appearance of a drunken, belligerent son interrupted the proceedings. Father and son exchanged harsh words, a punch was thrown, and the younger Jarrell ended up unconscious on the floor. Hardly missing a beat, Tommy Jarrell then delivered the for-the-ages reading of "Sorrows" featured on Disc 2.

I was introduced to County in a Chicago record shop one cold winter day in 1971. The album I found and purchased was More Clawhammer Banjo Tunes & Songs (County 717), the second of a three-LP set eventually re-released as CDs in the series Clawhammer Banjo in 2004. If you have that, you will have some of what's on Legends, including Fred Cockerham's "Roustabout" and Oscar Wright's "Elkhorn Ridge," two of the most compelling recordings of American folk music ever preserved for posterity. The rest -- the bulk of the collection -- had been available only on LP before now, or had never been released in any form. The quality is not only unceasing but sometimes intimidating. I'm not sure the human ear and heart are built for exposure to more than a hundred cuts of this at a single listening.

Legends of Old-Time Music, however, is essential, a thing of joy, wisdom and undiluted pleasure. Freeman, Nevins and Faurot (who died in 2011) will probably never be as celebrated as Southern-folksong collectors Cecil Sharp and the Lomaxes -- indeed, the very term "folk song" still seems to make Freeman uncomfortable, though it's employed freely, as it needs to be, in the notes -- but they deserve such acclaim. Start with Legends, which is just the top of a towering musical mountain, and follow the trail that winds through County's vast catalogue. That catalogue marks an enduring testament to the vision of three pioneers who rescued some of America's finest music and musicians from an oblivion that would have amounted to a national tragedy.