In September 1997, Mariah Carey released her sixth studio album. It was also, in many ways, her first. “[It’s] still my favorite album,” she wrote of Butterfly, which celebrates its thirtieth anniversary next year. “It represents artistic freedom—and freedom in general—for me. A huge personal turning point.” The emphasis on self, even in these two lines, is hard to miss. Butterfly was singular because the album’s sound and structure were produce…