ButIacceptedtheinvitation.Key?tz'ssuggestionthatweincorporatesome of my earlier work on matrix population models seemed like a good way to complement the methods presented in the book, and to expand the range of their applications. I am a demographer of plants and nonhuman animals. Some would call this an oxymoron, since the Greek rootdemos refers to people, and that's us. But there are precedents for taking more inclusive de?nitions of the Greek.Ecologyandeconomics, forexample, bothcomefromtherootoikos, referring to the household. Interpretingdemos as referring to individuals, whether they...