This book discusses the relationship between cellular immunity and tryptophan metabolism, as well as its products, serotonin and melatonin, in the development of several diseases and reappraises the common signal transduction pathways of the neurodegenerative diseases, carcinogenesis, immune tolerance, inflammation, hypersensitivity reactions, neuropsychiatric disorders, in addition to bacterial tryptophan biosynthesis and novel antimicrobials. Tryptophan Metabolism: Implications for Biological Processes, Health and Disease presents fundamental information on tryptophan related metabolic pathways and metabolites, implications of these products for specific biological processes, diseases and conditions. This book focuses on effects of tryptophan metabolites on human health and will appeal to researchers, clinicians and students within this field.