The book consists of a total of 17 chapters contributed by experts from ten different countries across the globe. The book is divided into six short sections containing a minimum of two chapters each. It is a comprehensive collection of articles that describe the active processes performed by micro-organisms in our daily life, in both a positive way, which is emphasised, and less so in a negative way. The book is focused more on the benefits that mankind can harness from these microbes with which we interact constantly. As we live in complete harmony with these Leeuwenhoek's animalcules, we must learn to achieve and maximise the benefits from such microscopic organisms.