Yes, his book and he are referred to in the article several times. I haven't read "Collapse," I'm sorry to say. (Nor "Guns, Germs, and Steel.") I have read a number of theories on the reasons for the collapses of various empires, each sincere and convincing and mutually exclusive of the other theories. My lesson from this is that it's probably not wise to ascribe _a_ reason to anything. I'm comfortable with my own assumption that there are many reasons why things go horribly right for some and horribly wrong for other civilizations.