While many scholars who write about animals deal with animal agency in some way, this volume is the first to position the question of nonhuman agency as the primary focus of inquiry. Section I presents studies of actual animals demonstrating agency; Section II moves agency into new terrain while considering key representations of animal agency in literature; Section III analyzes animals as mediators and as conveyances of human-to-human communication;and Section IV investigates the agency of beings who defy conventional species categories. The Envoi demonstrates how the microscopic polyp is interwoven into notions of agency and mythical superagency. This volume’s interdisciplinary explorations press hard on issues of agency to open up space for more questions about how we can understand relationships between the human and the nonhuman.