This book, Gut microbiome and Brain Ageing, deals with the mechanisms and phenomenon that relates gut microbiome and aging of the brain. This book will bring forth the connection between good gut and brain aging and includes some cutting edge research topics dealing with gut physiology and its importance as future therapeutic option in neurological disorders. The gut microbiome's impact on neuronal function, mediated by neurotransmitters, vitamins, and neuroactive microbial metabolites, is an exciting area of investigation that this book thoroughly explores. It also covers the pivotal role of the gut microbiome in the etiology of various neurodegenerative disorders such as Alzheimer’s disease (AD), Parkinson’s disease (PD), depression, or multiple sclerosis (MS). It also explores the expanding understanding of the importance of the early-life gut microbiota and its implications for long-term health consequences. This book primarily addresses researchers, clinicians, and doctoral andgraduate students working in biomedicine, neurobiology, nutrition, microbiology, and translational medicine streams**.**