The human microbiome refers to the complete microorganisms inhabiting the human body sites including skin, ear, nose, oral cavity, the genital, gastrointestinal and respiratory tracts, and body fluids such as breast milk, saliva, and urine. It is a significant and essential organ recognized for the body and has an established involvement in the host wellbeing, in terms of nutritional requirements and immunomodulation. This book talks about how alteration and imbalance in the same can have clinical implications associated with a multitude of gastrointestinal, lifestyle-associated, and neurodegenerative disorders. How the proliferation of specific groups of bacteria and their metabolic activities, as a result of intestinal dysbiosis leads to the 'leaky gut' condition thereby influences brain activity via the bidirectional gut-brain axis. It also coves the importance of microbial seeding and how it can be influenced by the mode of delivery, nutrition, and medication. This book also provides various therapeutic interventions such as the establishment of stool banks and Faecal microbiota transplantation (FMT) that have recently proved promising in the treatment of ASD, Inflammatory Bowel Disease, and Ulcerative Colitis. This book provides a deeper understanding of the development of the human gut microbiome and the factors driving its dysbiosis. This book is a valuable read for health professionals, medical students, nutritionists, and scientific research communities who are eager to update themselves with recent trends in microbiome research. It will also aid gastroenterologists and nutritionists to make well-informed choices regarding therapeutic regimes.