From the furthest part of the Arctic Ocean to the remotest spot in the Montana backcountry, the unmistakable traces of human activity are now everywhere. We live in the moment when “pristine nature” is permanently blinking out of existence. The most dramatic aspect of this distinctive moment in history, however, is the arrival of new technologies that promise even deeper transformations of the world around us. From here onwards, technologies like nanotechnology, synthetic biology, and climate engineering will transform our planet into an increasingly synthetic whole. Christopher Preston shows how many of these nature-replacing technologies may be necessary, but also how they may risk cutting us loose from the things that keep us sane.