In Jamaica, before reggae and rocksteady, there was ska. Emerging in the late 1950s, ska was a combination of calypso, American jazz and R&B. Ska evolved as Jamaican singers and musicians put their own spin on the sound of American pop records that were played on large sound systems built for neighborhood parties. As ska grew in popularity, it developed its own rhythms, horn riffs, dance style and independent record labels. By the early 1960s, the ska sound made its way onto the American charts with Millie Small's My Boy Lollipop (1964), which peaked at #2 on the Billboard pop chart. Here's Small singing her hit song...
So where did this churning, jagged music come from in Jamaica and which groups were ska pioneers? Here's a 35-minute Jamaican documentary I found from 1964, Ska, Ska Ska (also known as This Is Ska)...