Recently in a CD review of "Harmonica Blues: Great Harmonica Performances Of The 1920s And 1930s" I noted that they great harmonica players of that period were hamstrung (at least out in the country) by the lack of electricity in the Saturday juke joints and so the sound was somewhat tinny. However I also noted that the basic configurations produced in that period would be transformed by later harp greats into magic by electrification. And the album under review, Blues Harp, is proof positive of that assertion.
No question the post-World War II (and before too) black migration north to the cities and city industrial jobs (especially during the war) changed the slow back country beat music in profound ways. The electric "juice" provided at urban Saturday night (and Sunday morning, Sunday morning before repentance, okay) played a great role in bringing the harmonica (through close mouth association with the microphone) to its central place in the great golden age of the electric blues (part one) before rock and roll blew everyone away (for a while, and then we hungers back again for roots music, for that primordial connection with ancient times, and ancient lusts).
And they are all here, or almost all, the great ones that is, although the classic one that I keep coming back to is Howlin' Wolf fooling around with
"How Many More Year" down at early years Newport Folk Festival when he practically inhales the harmonica. Wow. Crank up YouTube for that one. In the meantime the cast here will give you the role of honor in the golden age night, Sonny Boy Williamson, Junior Wells, James Cotton, Snooky Pryor, the Wolf Man of course, and some others who history had previously left in the shadows, How many more years, indeed.