There was a mystery novel written on the topic some few years ago. The title included Crossroads, but I can't remember if it included "Old Sratch". Took a quick glance in the shelves but didn't see it, will look when I get back from my trip.
When I first bought a guitar (1949) the songs I learned and loved were a bit eclectic. John Jacob Niles with his English, Appalachian from various, and particularly Huddie Ledbetter from the Lomax tapes. B.B. King's blues are beautiful, with the squeezed guitar. But so are the simple sounds of Leadbelly. Best, Jon