Current debates in the environmental humanities, animal studies, and related fields increasingly revolve around this question: What to do with "the human"? Is the human a category worth preserving? Should it be replaced with the post-human? Should marginalized and minoritarian groups advocate for a universal humanism? What is the relationship between humanism and anthropocentrism? Is a genuinely non-anthropocentric mode of thinking and living possible for human beings? This book argues that the writings of twentieth-century poet Robinson Jeffers offer twenty-first-century readers a number of crucial insights concerning such questions and timely advice about how not to be human. For Jeffers, our tendency to turn inward on ourselves and to indulge in human narcissism is at the heart of the social, economic, and existential ills that plague modern societies. As a remedy, Jeffers recommends turning ourselves outward--beyond the self and beyond the human--and learning to affirm and even love the inhuman cosmos in all of its terrible beauty. In articulating this vision of "inhumanism," Jeffers develops a full-orbed and radical non-anthropocentrism that stretches across ethical, political, ontological, and aesthetic registers. In the process, Jeffers helps us find our way back to ourselves, but this time no longer as "human" in the traditional sense but as plain members of the inhuman world. With his inhumanist philosophy and poetics, Jeffers not only anticipates the most pressing questions and cutting-edge debates of our present moment but also challenges us to reconsider some of the key dogmas that underpin familiar discourses surrounding the Anthropocene and posthumanist philosophies and ecopoetics.