This book explores the ways Robert Smithson’s art revealed and defamiliarized the constructs of rational reality in order to allow radically speculative alternatives to emerge. In this way, his art is conceived as a true fiction that eradicates a false reality. By tracing the web of correspondences between Smithson and science fictional, speculative and mystical modes of thought, Rory O’Dea explores the aesthetic encounters engendered by his art as a means to warp the contours of reality and loosen the boundaries of being human. Given the current and impending catastrophes of the Anthropocene, which represents the ever-expanding planetary shadow cast by humanism, the possibility of being other-than-human posited by Smithson’s art is a matter of urgent concern. The book will be of interest to scholars working in art history, contemporary art, American studies and environmental humanities.