I would also recommend looking at the works of Timothy Ely, a book artist in Oregon (I think he lives in Oregon). His works are each one of a kind. They are like field notes by an alien, or maybe an Atlantean. I had the pleasure of hearing him give a presentation with some of his works, a number of years ago, which was fascinating; he will tumble river rocks from the stream on his property and use the resulting rock dust as pigment, or take paper out and mash it around in vegetation to get a particular effect.
And a short video about his creative process;
