IN THE SIXTIES many of the biggest blues names went on annual tours of Europe, giving thousands of fans their first taste of real blues. Now researchers have discovered film of their performances shot at a German TV studio - and the results are breathtaking. On the two volumes of The American Folk Blues Festival 1962-1966 (Universal) we can see the likes of Muddy Waters, Howlin' Wolf, Sonny Boy Williamson and T-Bone Walker at the height of their powers.

There's a snappily dressed Muddy, purring through I Got My Mojo Working; Sonny Boy, huge hands dwarfing his harmonica as he takes us Nine Below Zero; Howlin' Wolf, sitting in a make-believe juke joint telling us I'll Be Back Someday. But most poignant of all is the bonus footage of Magic Sam, a mercurially talented Chicago guitarist, playing his much-covered All Your Love on a clip from the 1969 tour. A few weeks later he was dead at the age of 32 from a heart attack. As the producers of these Grammy-nominated sets rightly say, these are national treasures.