With his acoustic sound and hippie anthems like "Blowin' in the Wind," Bob Dylan was elevated to the high ranks of folk music royalty by the time he hit his early 20s. After wowing crowds at the Newport Folk Festival in 1963 (as a guest of Joan Baez) and in 1964 (where he was introduced by Ronnie Gilbert of The Weavers), his third appearance in 1965 was a hugely anticipated event. But ambling onto the stage that day, Dylan was already chafing at the expectations of folkie purists. Instead of giving his 100,000 fans what they wanted, he went electric. Legend has it Dylan's treachery inspired boos, accusations of selling out, and even drove peacenik Pete Seeger to the brink of violence.

That iconic performance, fifty years ago this month, changed the whole trajectory of pop music, says Rob Bowman, a musicologist and professor at York University in Toronto. Guest host Rachel Giese speaks to Bowman about the significance of Dylan's folk rebellion and his impact on rock n' roll.