Leadbelly

I've never heard such soul-wrenching, delightfully grim blues in my entire life.
many of the folk tunes he performs are old "negro prison songs" that he delivers with unmatched sincerity.
really great stuff, if anyone is interested, I'll upload what I have.
otherwise, many many tracks are available here.

also, he performed the first recording (as far as I know) of the later Ram Jam covered hit, "Black Betty."

MMM