If nature is what lies beyond human society, then animals must be a part of it. 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 the wilderness. They are also real creatures and individual subjects with whom we have diverse and complex relationshipsScholars, however, tend to treat animals and the environment as distinct, mutually exclusive objects of interest and concern. Conducting the first systematic examination of the place of animals in scholarly and popular thinking about nature, Anna L. Peterson builds a nature ethic that conceives of nonhuman animals as active subjects simultaneously a part of nature and human society. Disrupting the artificial boundaries separating these two realms, Peterson explores the tensions between humans and animals, nature and culture, animals and nature, and domesticity and wildness, and she uses our intimate connections with companion animals to examine nature more broadly. Liminal creatures who straddle the boundary between human society and wilderness, companion animals reveal much about the mutually constitutive relationships binding humans and nature together. Through her paradigm-shifting reflections on animals, nature, and ethics, Peterson underscores the fluid and continuous character of two seemingly immutable categories.