Most people know that the digestive tract contains billions of helpful gut bacteria, but how does the gut microbiome affect our health? What exactly do these bacteria do, and what are the negative effects when these microorganisms are harmed by what we eat and do? What impacts might they have on conditions such as irritable bowel syndrome (IBS), obesity, and autism? This book provides an accessible, holistic introduction to the study of the human gut microbiome and its effects on digestion and disease—one of the newest and most rapidly expanding fields in medicine today. The gut microbiome is known as "the forgotten organ" because it is not identified as part of the human body per se, yet it has an immense influence on many systems in the body. explains what the microbiome is, the many functions it serves, how it can be either harmed or supported by our actions, and the role it may play in various diseases and in determining our overall health. The book examines the various potential causes of imbalance in the microbiome, such as diet and other lifestyle factors, and then identifies strategies for improving human health by protecting the gut microbiota. The science-based information is detailed but accessible to general readers or students without extensive background knowledge.