This updated edition contains new chapters on antioxidant defense systems in bacteria, plants, and animals; the detection of free radicals; the role of antioxidants in aging, nutrition, disease, and therapy; and a new appendix on molecular biology. The chapter on oxidative stress and its consequences includes the damage and repair of DNA, proteins, and lipids, cytokines, and cell death (both apoptosis and necrosis). Free radicals and other reactive species are now implicated in a number of diseases and this edition covers their role in hypertension, diabetes, lung damage, cystic fibrosis, nervous system disorders, viral infections, and cancer.