For most of human existence, microbes were hidden, visible only through the illnesses they caused. When they finally surfaced in biological studies, they were cast as rogues. Only recently have they immigrated from the neglected fringes of biology to its center. Even today, many people think of microbes as germs to be eradicated, but those that live with us—the microbiome—are invaluable parts of our lives.

I Contain Multitudes lets us peer into that world for the first time, allowing us to see how ubiquitous and vital microbes are: they sculpt our organs, defend us from disease, break down our food, educate our immune systems, guide our behavior, bombard our genomes with their genes, and grant us incredible abilities. While much of the prevailing discussion around the microbiome has focused on its implications for human health, Yong broadens this focus to the entire animal kingdom, giving us a grander view of life.

With humor and erudition, Ed Yong prompts us to look at ourselves and our fellow animals in a new light: less as individuals and more as the interconnected, interdependent multitudes we assuredly are. When we look at the animal kingdom through a microbial lens, even the most familiar parts of our lives take on a striking new air. We learn the secret, invisible, and wondrous biology behind the corals that construct mighty reefs, the glowing squid that can help us understand the bacteria in our own guts, the beetles that bring down forests, the disease-fighting mosquitoes engineered in Australia, and the ingredients in breast milk that evolved to nourish a baby’s first microbes. We see how humans are disrupting these partnerships and how scientists are now manipulating them to our advantage. We see, as William Blake wrote, the world in a grain of sand.

I Contain Multitudes is the story of these extraordinary partnerships, between the familiar creatures of our world and those we never knew existed. It will change both our view of nature and our sense of where we belong in it.