"Oh, I have seen the David," sings Guy Clark. "Seen the Mona Lisa, too. And I have heard Doc Watson sing 'Columbus Stockade Blues.' " My own favorite Doc Watson moment is more modest. It came the last time he appeared at the Ann Arbor Folk Festival, as he got ready to sing a song by the Blue Yodeler, Jimmie Rodgers. "This isn't really an old-time song," he said. Then, a trifle disdainfully: "Unless you consider the twenties old-time."

Much can be said (and probably will be, in advance of Watson's January 26 appearance at the Ann Arbor Folk Festival) of Watson's tremendous influence as a guitarist and banjoist — never flashy, he has a hypnotic way of exploring small musical spaces. For me, though, Watson as singer of songs is most compelling. His performances open up a view of American music in which the 1920s do seem fairly close at hand.

The point is not that Watson's repertoire skews toward an older, purer layer of folk music than those of the other southeastern performers who came to prominence during the 1960s folk revival. A working country musician for many years before he ever heard of folk music, Watson is adept at incorporating new pieces into his repertoire. Not long ago he recorded an entire album of rockabilly songs, and, as with all the very greatest white country musicians, the blues have touched nearly every number he does.

Rather, a Watson performance seems to capture whole a very old way of making music and being a musician. Blind since childhood in Deep Gap, North Carolina, Watson learned to play music on a homemade banjo given him by his father. He played for tips on street corners for a time. On stage Watson is a griot-like figure — a storyteller who carries centuries of cultural memory. His songbag ranges from medieval England to the present day, and his concerts, never the same twice, carry wisdom on top of beauty.

Watson is an icon of the 1960s rediscovery of folk music, and his popularity has never waned since he appeared at the Newport Folk Festival in 1963. I wish the State Department had sent him out on one of those goodwill tours meant to show the world the best of American culture. True, there have been previous warnings of a "last chance" to see the seemingly indestructible Doc Watson. But the man's nearly eighty. Don't miss this one.