In the mid-1960s the times they were indeed a-changin.One of the places those changes were being felt was the world of folk music, says rock historian Elijah Wald, author of a new book, Dylan Goes Electric.There was a moment in the early 60s where you could look at the Billboard chart and seven of the top 10 albums were folk records.And Joan Baez, Peter Paul and Mary, the Kingston Trio, all had huge, huge, huge number-one records.And then all that changed.In 1964, the Beatles had hit and by the summer of 1965 a lot of people in the folk scene were sort of feeling like their world was threatened.They were hoping that Bob Dylan would come to the rescue.