The harmonica is the ultimate populist instrument, small enough to fit into a shirt pocket and expressive enough to beat the band. The harmonica became so central to the blues that picking a sampler album is an unenviable task. Classic Harmonica Blues includes tracks from the 1950s and ’60s, when blues remained the popular music of rural African Americans, as well as lots of numbers from latter-day festivals. All are suffused with the genre’s characteristic resilient sadness and hopeful resignation, and showcase how the humble harmonica can challenge the guitar for sonic dominance.