Hoodoo Man Blues
I bought this album on a Delmark LP about 44 years ago, mail order direct from Chicago and it still sounds superb (I also have the CD). It was one of the first "Blues albums" as opposed to "a collection of singles" and set the standard which others are still trying to emulate. It became the template that many bands (my own included) tried to follow. Blues has got a lot louder since then but never as modern as this.