This fully updated and revised edition of Professor Postgate's best-selling book provides an inspiring introduction to the fascinating world of microbes and their profound influence on man and the environment we live in. Microbes are everywhere. In the air, in soil, in water, on our skin and hair, in our mouths and intestines, on and in the food we eat. They make the soil fertile; they clean up the environment; they change, often improve, our food; they make vitamins for us inside ourselves; some protect us from less desirable microbes. As 'germs', microbes are regarded as nasty, because a few can cause disease, a few can spoil food, a few can destroy valuable materials. Only when such misfortunes occur are most people conscious of microbes at all. Yet collectively, microbes present a fascinating world of invisible, or barely visible, creatures, which together encompass all the processes of which terrestrial life is capable; creatures which have had, and continue to have, profound effects on our lives and surroundings. In this book, John Postgate explains to ordinary non-scientist readers the impact this invisible community has on our everyday lives, and conveys the excitement microbes can generate in those who study them.