This section is concerned with the structure and use of theory. Following Pickett, Kolasa and Jones (1994) we recognize the value of explicitly laying out methods and conceptual constructs for building theory and promoting intellectual integration. This effort relies on a long history of development in the philosophy of science that we will not do justice to here, as our goal is to provide only a brief overview of the nature of theory, motivations for its development, taxonomy, anatomy, ontogeny, and some of the environmental contexts in which it is found. Together, these constitute method-for-theory. This framework will then be used to sketch the raw beginnings of an integrative theory of human ecosystems in Section II.