Restless Blood and Jungle Rhythms.

At a time when America's most serious domestic problem in the minds of many people was the integration of schools, when federal integration laws were being defied across the nation, when angry parents were rioting in the streets to protest being forced to share public facilities with blacks, American teenagers became infected in epidemic proportions with an insatiable urge to dance to what their parents called jungle rhythms. Rock 'n' roll was a musical revolution in which young people, white and black, united in spirit, if not in person, outside segregated schoolhouses to adopt a criterion for musical judgment that had never been widely accepted before. Emotive expression laid over an insistent backbeat were the primary elements of the music they danced to — not pleasing melodies, clever lyrics, or even virtuosity.

Soul.

If a performer had soul...