Fungi are everywhere. Most are harmless, some are helpful. A few are killers. Collectively, infectious fungi are the most devastating agents of disease on Earth, and a fungus that can persist in the environment without its host is here for the long haul. In gripping, accessible prose, Emily Monosson documents how changing climate, trade and travel are making us all more vulnerable to invasion. Populations of bats, frogs and salamanders face extinction, and scientists don’t have a cure. The American Northwest’s beloved National Parks are covered with the spindly corpses of white bark pines. Food crops are under siege, threatening our coffee, bananas and wheat—and, more broadly, our global food security. In humans, Candida auris infects hospital patients and those with weakened immune systems. Monosson’s critical reporting demonstrates that prevention is difficult but not impossible. Exposing the connection between pathogens and human action, Blight serves as a wake-up call, a reminder of the delicate interconnectedness of the natural world.