David Quammen published this fascinating, terrifying book a decade ago when the world had already fairly recently grappled with AIDS, Hong Kong flu, SARS, H1N1, Legionnaire’s diseases, Ebola, and Marburg, among others. All these viruses were zoonotic—that is, they emerged from animals into humans—and Quammen’s book sets out to distill the best scientific thought on how these little buggers adapt and change to successfully use the human body as a place to grow and mutate to sustain their survival. Quammen traces the biological detective work conducted on the part of epidemiologists and others to identify these zoonoses and understand the ways in which they jump from bats or rodents or chimps into humans. Parts of the book are like a disease-based travelogue, in which he visits the world’s scariest bat caves and gorilla nests to follow the science. He has an admirable knack of making complex science intelligible and even interesting. He wrote this book long before the current coronavirus, but he predicted there would be more. He speculates that human beings themselves constitute an outbreak, having doubled our population since 1969 and adding 1B every year since then (496). The sheer size of the human population means we are pushing into formerly unspoiled areas, coming into more and more intense contact with the animals that live there, changing the climate, and exhausting resources. But his goal is not to frighten the reader, but to point out that only human behavior can defend against the next mindless pandemic. “Individual effort, individual discernment, individual choice can have huge effects in averting the catastrophes that might otherwise sweep through a herd,” he writes (519). Our miserable bungling of the COVID-19 crisis, however, points to the ways in which self-preservation can fail. As I write this, since the start of the pandemic in early 2020, 96M cases have been diagnosed globally, with 1M dead (and those are the reported cases and deaths).