Progressive rock, or prog rock as it is more commonly called, evolved primarily in England from the late 1960s through the late 1970s. In some respects, the genre was a symphony-suffused offshoot of psych rock, but prog rock also included elements of jazz and musical theater, with long guitar and keyboard instrumentals that routinely broke the short-form molds of top-40 radio, and albums that often revolved around themes and...Continue Reading