This book presents topical research in the study of the dietary sources, functions and health benefits related to tryptophan. Topics discussed include molecular imprinting for chiral separation of tryptophan; tryptophan ingestion improves the synthesis of serotonin and melatonin and may be related with delay of some conditions of aging; the role of tryptophan residues in antimicrobial activity and membrane interactions; the health benefits from tryptophan supplementation in humans and the metabolism of tryptophan and evaluation of tryptophan supplmentation on fish larval growth and frequency of skeletal deformities.