I love and would recommend the Harry Smith Smithsonian Anthology to anyone. I decided to recommend the Bristol Sessions discs because (a) they're less well known, and (b) they're only two discs, so it's less of investment, so people might be more likely to try them. For those interested, the Harry Smith Collection is linked below.

As for the "harp-guitar" . . . you've got me!

• Smithsonian Anthology of American Folk Music (Edited by Harry Smith)