The final five years of the team of Flatt & Scruggs is documented on the six-CD Bear Family set 1964-1969, Plus. Their final six recordings together are on a Lester Flatt box set on the same label (Flatt on Victor Plus More, Bear Family 15975). Though the pair never referred to themselves as bluegrass musicians -- because of its association with their mentor, Bill Monroe -- they had a difficult time telling the ever-increasing flood of international fans just what it was they did. Certainly it was folk music, but not the folk music of the folk revival of the late '50s and early '60s, and it was country music, though not what Owen Bradley and Chet Atkins was pushing through Nashville at the time, and while a lot of the music was rooted in blues and gospel, it couldn't be called that either. Flatt & Scruggs were the progenitors of what later pioneers like Tony Trischka, Randy Scruggs, Béla Fleck, and others would call "newgrass" -- the pair wouldn't have liked that either. What this set documents is how the musical styles emerging in the 1960s were explored by Flatt & Scruggs, were turned inside out, were popularized, and put enough pressure on the duo, musically and professionally because of increased fame, to tear them apart. Here are the recordings of Waylon Jennings' "I'm a Man of Constant Sorrow" (before Ralph Stanley cut it), Bob Dylan's "It Ain't Me Babe," Tom Paxton's "The Last Thing on My Mind," Chuck Berry's "Memphis," "Foggy Mountain Breakdown" done for the film Bonnie & Clyde, traditional songs like "Sally Goodin," Mel Tillis and Danny Dill's "Detroit City," Tom T. Hall's "I'm Gonna Ride That Steamboat," John Sebastian's "Nashville Cats," Doc and Merle Watson's "Southbound," and Flatt & Scruggs' amazing instrumental "Jazzing." But before the reader looks away in disgust, muttering "sellout," perhaps the music itself should be taken as an example of its own merit. Flatt & Scruggs stood outside of tradition from the beginning by breaking with standard vocal and instrumentation regimens. Using four-part harmonies, drums, and harmonica on a Dylan song, the duo were merely doing what they had done throughout their careers -- they explored the roots of a song and discovered where it took them. Recording Buffy Sainte-Marie's "Universal Soldier," Donovan's "Catch the Wind," Dylan's "Wanted Man" and "Like a Rolling Stone," the Hall songs for the Bonnie & Clyde soundtrack, and Bobbie Gentry's "Ode to Billie Joe" were high-wire acts, cliff edges both men were looking over into an abyss that refused to stare back at them, and finally it separated them. But it was never for lack of an adventurous spirit of laziness or lack of respect. What is documented here may be the sound of disintegration, but it is also the sound of courage and preservation that brought the heart and soul of country music to popular music, not the other way around.