Who is Blind Blake from Killing Floor and what is their importance?

Blind Blake was a guitar player that died sixty years ago under questionable circumstances. The information that he had been killed in Margrave came from a record sleeve that was owned by Joe Reacher, and he told the story to his brother, Jack. It was the story of Blind Blake that had Jack stopping in Margrave. Blind Blake played with such grace that the barber's sister used to sing with him every chance she got.