This edited volume studies gut microbiota peculiarities in elderly, in senescence-related  and environmental-related alterations of gut microbiota in chronic diseases.Aging, as a physiological process mediated through several regulatory pathways and transcription factors, is generally speaking associated to a relentless functional decline and increasing risk of chronic diseases. Growing data on gut microbiota quali-quantitative changes in aging gut, and the opportunity to study by advanced NGS and metabolomic technologies, now offers novel horizons to link such changes to disease risks and...