In this groundbreaking book, Alanna Collen explores the extraordinary world of the powerful microbes that make up 90 percent of the human body.

You are just 10 percent human. For every one of the cells that make your body, there are nine impostor cells. You are not just flesh and blood, muscle and bone, brain and skin, but bacteria and fungi. You are not an individual but a colony of microbes. Far from being passive, the trillions of microbes that live on and in you are intimately involved in running your body. Even aspects that you think of entirely as ‘you' turn out to be run by ‘them' - like your immune system.

In this riveting, shocking, and beautifully written book, Alanna Collen explores the modern epidemics of ‘Western' diseases - obesity, autism, mental health problems, gut disorders, allergies, autoimmunity, and even cancer - and argues that most have their roots in our failure to cherish our most fundamental and enduring relationship: that with our personal colony of microbes. Antibiotics, antibacterial cleaners, rapidly changing diets, and our obsession with hygiene alter the microbe community we carry. Unlike our human cells, though, we can change our microbes for the better.

10% Human provides a revelatory guide to the role of your body's microbes in health and happiness. This is popular science at its most relevant: life - and your body - will never seem the same again.