This author is cited by Carl Gustov Jung in a manuscript about the Norse god Wotan (Odin). I believe this is the book where Martin Ninck is describing the god Wotan as a psychic phenomenon, which causes a variety of specific traits attrituble to this god. I cannot read German, but if you follow this link and scroll down to the last quarter of Carl Jung's essay, you'll find the description of Martin Ninck's book. http://allfatherwotan.org/essayonwotan.html