This is the first serious attempt to synthesize all that became known of glutathione over the last three decades. The book contains an update of glutathione biosynthesis with special emphasis on its regulation in adaptive stress responses. Other chapters review glutathione transport systems and glutathione peroxidases and their differences in substrate specificities and localization. Further contributions center on the diversified roles of different glutathione-S-transferases and the roles of nitrosoglutathione and glutaredoxins - a subfamily of redoxins. The book closes with discussions of the analogous or homologous thiol metabolism in pathogens and the potential suitability of involved enzymes as drug targets.