Less of a traditional genre than a specific blend of mountain music, square dance, blues and gospel created with the arrival of guitarist Lester Flatt and banjoist Earl Scruggs in Bill Monroe’s band in 1946, bluegrass dominated commercial country music in the late ’40s. Back in the spotlight again in the wake of the success of the Coen brothers’ movie O Brother, Where Art Thou?, this 54-track double CD of bluegrass’ greatest names includes the centrepiece from the film’s multi-million-selling soundtrack, the Stanley Brothers’ “I’m A Man Of Constant Sorrow”.