John Jackson was one of those blues musicians who'd given up playing (by the end of the 1940s in his case) before being "rediscovered" in the Sixties blues boom, and going on to make a decent living out of recording and live appearances. Here he is in 1997, well into his seventies:
Jackson played the Piedmont style, in the tradition of Blind Blake and Blind Boy Fuller.
And here's a nice interview with the man from 1993 by Elijah Wald.
He died in 2002.