Biomimicry by Janine Benyus - Fascinating idea--philosophy, really--that we should look to the existing designs of nature for "innovation."
Not that such an approach isn't being used. Look at how pharmaceutical companies develop compounds found in rainforests into new drugs.
But biomimicry as Benyus describes it is something deeper. It's about changing how we view ourselves in the world as much as how we seek out nature-inspired design.