They sculpt our organs, protect us from diseases, guide our behaviour, and bombard us with their genes. They also hold the key to understanding all life on earth. In this book Ed Yong, a debut writer with a huge following, opens our eyes and invites us to marvel at ourselves and other animals in a new light, less as individuals and more as thriving ecosystems. A genre-busting book on microbes, one of science's hottest topics and a New York Times bestseller.