Until recently, most genetic engineering has been limited to domesticated species like crop plants, livestock, and lab animals. But Crispr and other next-generation editing techniques have made it much easier to alter the genomes of more exotic species, and even to have targeted impacts on entire ecosystems. Using cases he has explored in depth—including the transgenic chestnut, the gene-drive mosquito, and the de-extinction of lost flower species–award-winning science writer Rowan Jacobsen explores the ethics and implications of this new power humanity is about to exert on the natural world.