The Butterfield Band's debut album from 1965 was traditional Muddy Waters-style Chicago blues but played with real power and authenticity that was miles ahead of any British band. It's hard to imagine now the impact it made at the time but I remember my jaw literally dropping when I heard the tough, forceful sound of "Born in Chicago" for the first time. Butterfield's harp is very much to the fore in many of the tracks and he gets a great thick, dirty wedge of sound that again no British player could get anywhere near. It's very much an ensemble record, played in an uncompromising traditional style and featuring wonderful songs by Elmore James, Little Walter and Junior Parker.
Although Butterfield didn't mean a great deal in Britain, in the States he was Alexis Korner and John Mayall rolled into one and inspired many of the harp players that came after him - Magic Dick, Kim Wilson, James Harman etc etc.