Some fields of law have fairly clear boundaries. Not so with environmental law. In order to say anything with the least bit of clarity about the field of environmental law as such, you need some sense of what does and doesn’t count as part of the field. I have a simple model of what counts, for my own purposes. In this entry, I will explain my model of the field, and also talk about some of the limitations and unresolved boundary issues with my model. It starts with a recognition that law has long been concerned with two related things, natural resources and waste.