Glutathione (GSH) is a ubiquitous tripeptide (y-L-gluatamyl-Lcysteinyl-glycin) playing an important role in cellular redox homeostasis, defence against electrophilyc reactive species, and control of several cellular events, among others. Most of these cellular functions are related to its tiol (SH) function of the cysteine moiety. With increasing knowledge on the molecular basis of its cellular functions, use of GSH as a nutritional supplement is receiving increasing interest. The present book summarises the recent literature and new develeopments on three distinct, but closely related topics: Production, biochemical functions, implications and applications of glutathione. The topics cover comprehensive reviews on physico-chemical characterization, pharmacopoeal qualification, biotechnological production, surveys on different analytical methods for its quantitation, and the role of several physiological abnormalities (e.g., cardiac disfunctions, neurological disorders, kidney injuries and different types of cancer) related to non-appropriate biosynthesis and/or metabolism of endogeneous GSH. The information presented represents a valuable source for advanced students, scholars, teachers and scientists (academic and industrial) interested or already engaged in research that involves glutathione.