This book addresses the theme of what «nature» is and humans’ obligations toward the natural world. It demonstrates that an approach based in metaphysics can help us to understand better what nature is and our obligations to the natural world. Beginning with ideas traced from Aristotle through some of the signifcant figures in European philosophy, the author shows that each living thing is a unique source of value. He then argues that this value puts humans under an obligation and that adopting an attitude of responsibility to living things is an essential part of what it means to be human.