The peroxiredoxins represent an important emerging family of sulfhydryl-linked antioxidant proteins, apparently ubiquitously present in all known organisms. The antioxidant function of the peroxiredoxins complements that of other enzymic and non-enzymic systems within the cell. In addition, there is increasing evidence that the peroxiredoxins play a role in cell signalling, by controlling and/or sensing hydrogen peroxide and peroxynitrite levels. In this, the first book containing a broad survey on the peroxiredoxins, the editors succeeded to involve almost all groups that contributed significant insights into the emerging field. The diverse biological roles of the new protein family are discussed in the context of other antioxidant systems like those based on heme or selenium catalysis. Finally, related future perspectives, which range from antimicrobial therapy up to the understanding of human development and carcinogenesis, are highlighted. Specifically, the book will be of outstanding interest to researchers who want to understand how micro-organisms, plants and animals cope with oxidative stress and how such stress is recognized and linked to adaptive responses via redox regulation of cellular processes.