Toward Ecosophy

The difficulty I find with books on the subject is that numerology is very simple -- there isn't enough of it to fill a book! -- and so all the books I've found so far clutter it up with stuff that doesn't necessarily work too well. Numerology Made Plain by Ariel Taylor is decent, and Manual of the Enumeration by C.J. Coffman is weird but useful. Matthew Oliver Goodwin's Numerology: The Complete Guide is way over the top but has some very good material in it.