Starting with the Skatalites, Jamaican recordings largely revolved around a select floating pool of the island's best musicians; top producers began calling on the Revolutionaries in the mid-'70s. The group's importance, however, extends far beyond providing music to many roots classics; Revolutionaries backing tracks dominated Jamaican music when dub, the foundation of the mix culture, became a widespread reggae phenomenon. The group pioneered the four-beat "rockers" rhythm on recordings like the Mighty Diamonds' 1976 Right Time, as well as more syncopated variations on songs...