<<but what can anyone tell me about "Voices: The Work of Joni Mitchell" -- is this actually a serious analysis of her "work" (and would that include both visual arts and music), or a hack biography, or what?>>
Walt, Gilles Hebert is the curator of the Mendel Art Gallery in Saskatoon; "Voices" is the souvenir book published from the exhibition. Beautifully done, it is a collection & discussion of her painting, and wouldn't be much help to you with the piano except it might inspire you to compose some nice tunes! ;~) Bob NP: Buckingham-Nicks, "Goldfish & Ladybug" (Hi Nikki!)
