Over his nearly 50-year career Herbie Hancock has experimented with all kinds of genres, including classical, jazz, funk, and hip-hop. Hancock can now add folk to the list. His latest record is River: The Joni Letters, and on it he finds a kindred spirit in the music of Joni Mitchell. Hancock tells Kurt that when he first met Mitchell in the late 1970s he was surprised by what he heard.