Thomashow's main goal is to help teach the effects of climate change and extinction at the local level. He doesn't go off any theoretical deep ends--he integrates scientific, spiritual, and personal thoughts on "place" and nature observations into a beautifully conceived book.
I was impressed by his sophisticated ethic of "bioregional cosmopolitanism" that's much needed in a field that often over-romanticizes the local. He shows how migration, diaspora, and painful exile are part of the biosphere--and not just among humans.
Frankly, anyone interested in the world today should pick this book up. It's based in environmental studies, but touches on everything from art to religion to global business.