The microbiome is the missing link in modern medicine: a vast genetic universe of bacteria, yeasts, viruses and parasites that live inside us, influencing every aspect of our health, even the way we think and feel. In this mindblowing book, scientist and surgeon James Kinross explains how the organisms that live within us have helped us evolve, shaped our biology and defined the success of our species. But just as we have discovered this delicate and complex ecosystem within us, it is being irrevocably destroyed through the globalisation of our diets and lifestyles, our addiction to antibiotics, and the destruction of our environment.