There are many examples apart from Bob Copper - as detailed by Fred, Jim and others - which expose the false dichotomy between "peasant" and "professor". I chose Bob deliberately, not just because he studied his family's singing tradition and described it with exceptional eloquence, not just because he was self-educated to a high degree of expertise on a variety of subjects from local architecture to blues music, not just because he was himself a collector who delighted in turning up different versions of songs he knew, and not just because he liked to describe himself with self-deprecating irony as a "peasant", but because singing was to him essentially about having a good time. His knowledge never compromised that, nor does it for all those other singers of old songs who have sufficient curiosity to want to know something about them.