Obesity, autism, mental health problems, IBS, allergies, auto-immunity, cancer. Does the answer to the modern epidemic of 'Western' diseases lie in our gut? You are 10% human. For every one of your cells, there are nine impostors hitching a ride. You are not just flesh and bone, but also bacteria and fungi. And you are more 'them' than you are 'you'. Your gut alone hosts 100 trillion of them and until recently we thought that our microbes didn't matter. This is all set to change as the latest scientific research tells a very different story, one where microbes run our bodies and becoming healthy is impossible without them. In this ground-breaking book, biologist Alanna Collen reveals how our personal colony of microbes influence our weight, immune system, mental health and even our choice of partner. This is a new way of understanding modern diseases - obesity, autism, mental health problems, gut disorders, allergies, auto-immunity and even cancer - as she argues they have their root in our failure to cherish our most fundamental and enduring relationship: that with our microbes. Illuminating many of the questions still unanswered by the human genome project 10% Human completely changes our understanding of diet, modern disease and medicine. The good news is that unlike our human cells, we can change our microbes for the better and this book shows you how. A revelatory and indispensable guide: life - and your body - will never seem the same again.