One aspect of Johnny Cash's appeal I touched on in my recent look at the Bootleg III: Live Around the World release was his appearance at the 1964 Newport Folk Festival. Cash's roots in folk music were deep; only his country roots were deeper. Once he signed with Columbia Records in 1958, he continued exploring folk tunes as he quickly became one of their top country stars. That built on the fame he'd established on Sun Records from 1955 on. Cash developed such a strong folk following that Columbia would advertise his releases in the most popular folk magazine of the time: Sing Out!