For most people, animals are the most significant aspects of the nonhuman world. They symbolize nature in our imaginations, in popular media and culture, and in campaigns to preserve wilderness, yet scholars habitually treat animals and the environment as mutually exclusive objects of concern. Conducting the first examination of animals' place in popular and scholarly thinking about nature, Anna L. Peterson builds a nature ethic that conceives of nonhuman animals as active subjects who are simultaneously parts of both nature and human society. Peterson explores the tensions between humans and animals, nature and culture, animals and nature, and domesticity and wildness. She uses our intimate connections with companion animals to examine nature more broadly. Companion animals are liminal creatures straddling the boundary between human society and wilderness, revealing much about the mutually constitutive relationships binding humans and nature together. Through her paradigm-shifting reflections, Peterson disrupts the artificial boundaries between two seemingly distinct categories, underscoring their fluid and continuous character.