Autobiography
Many who watch this doc will already know, but to others I highly recommend Miyazaki's Staring Point 1979~1996, published in the US in 2009 with a VIZ Media imprint. The frankness and detail with which Miyazaki discusses his better known and lesser known works is amazing, a real window on his creative process.
I can only hope for a subsequent volume that would cover later years and works.
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PS - Now that I've watched this doc, I have to say, though it must be seen, it's of less value than the book; there's less to be learned from it than from the book.