

Joining the ranks of popular science classics like The Botany of Desire and The Selfish Gene, a groundbreaking, wondrously informative, and vastly entertaining examination of the most significant revolution in biology since Darwin—a “microbe’s-eye view” of the world that reveals a marvelous, radically reconceived picture of life on earth. Every animal, whether human, squid, or wasp, is home to millions of bacteria and other microbes. Ed Yong, whose humor is as evident as his erudition, prompts us to look at ourselves and our animal companions in a new light—less as individuals and more as the interconnected, interdependent multitudes we assuredly are. The microbes in our bodies are part of our immune systems and protect us from disease. In the deep oceans, mysterious creatures without mouths or guts depend on microbes for all their energy. Bacteria provide squid with invisibility cloaks, help beetles to bring down forests, and allow worms to cause diseases that afflict millions of people. Many people think of microbes as germs to be eradicated, but those that live with us—the microbiome—build our bodies, protect our health, shape our identities, and grant us incredible abilities. In this astonishing book, Ed Yong takes us on a grand tour through our microbial partners, and introduces us to the scientists on the front lines of discovery. It will change both our view of nature and our sense of where we belong in it.
A glimpse inside

Yong challenges the traditional view of organisms as discrete individuals by demonstrating that all animals, including humans, are complex collectives—a host plus trillions of microbes. These microbial communities, or microbiomes, are integral to our development, immunity, and daily functioning. By seeing ourselves as ecosystems, we gain a deeper appreciation for the interconnectedness of life and the importance of maintaining microbial diversity for our own health.
The book dismantles the common misconception that microbes are simply harmful invaders. Yong shows that while some microbes cause disease, the vast majority are beneficial or even essential. Microbes help digest our food, train our immune systems, and protect us from pathogens. By understanding the positive roles of microbes, we can make more informed choices about health, hygiene, and medicine.
Ratings at a glance
- 1We Are Ecosystems, Not Individuals
- 2Microbes: More Than Just Germs
- 3The Microbiome Shapes Health and Disease
- 4Symbiosis Drives Evolution
- 5A Microbe’s-Eye View of the World
Popular quotes from I Contain Multitudes
“We are not individuals; we are ecosystems.”
“The world is not just teeming with microbes. It is built by them.”