Beneficial microbes exist naturally in the body and play a vital role in our health. They are called probiotics. Due to growing concerns in using chemically synthesized medicines and antibiotics, research on probiotics which are natural and safe alternatives, has increased. For centuries, probiotics have been known for producing important microbiota of antimicrobial compounds that increases our immunityto counter the harmful effects of pathogenic organisms. In addition, these microbes have new potential applications in the treatment and negating the side effects of other diseases. The study of probiotic organisms and their wide potential applications in industrial products for human and animal uses has thus gained momentum.With the enormous growth of the probiotic market, many countries have developed new regulations and policies for this class of bioproduct. This book provides a comprehensivereview on the research, applications, regulations and trade policies of probiotics. It servesas a reference and resource for undergraduate andpostgraduate students, researchers, companies, and policy makers who are active in fields related to functional food and feed, industrial biotechnology, nutraceuticals, and medicine. All chapters in this book have been written and edited by leading experts in the respective fields from academia, industry, or government.