1. Lipid Peroxidation and its Inhibition (E. Niki). Introduction. Lipids in Biomembranes. Peroxidations of Lipids in the Membranes. Inhibition of Lipid Peroxidation. Epilogue. 2. Electron Spin Resonance and Spin Trapping (P.J. Thornalley). Electron Spin Resonance of Free Radical Intermediates in Biological Oxidations. Electron Spin Resonance: Theoretical Principles. Practical Aspects of Electron Spin Resonance of Biological Systems. The ESR Technique of Spin Trapping. Free Radical Intermediates in Biological Oxidations: Classification of Biological Oxidation Mechanisms. Electron Spin Resonance Studies of Free Radicals in Biological Oxidations. Conclusions. 3. Transition Metal Ions and Antioxidant Proteins in Extracellular Fluids (J.M. Gutteridge, B. Halliwell). Oxygen Toxicity. Biological Antioxidants. Protein Antioxidants of Extracellular Fluids. Summary. 4. Sensitization and Protection of Oxidative Damage Caused by High Energy Radiation (P. Wardman). Introduction. Quantitation of Radiation Damage. Targets in Radiobiology: The Focus of Oxidative Stress. The Oxygen Effect in Radiobiology. Oxygen-Mimetic Compounds. Antioxidants as Radiation Protectors. Clinical Exploitation of Radiation Sensitization and Protection. The Oxygen Paradox: Is it a Sensitizer or a Protector? Conclusions. 5. Interactions of Melanin with Oxygen (and Related Species) (T. Sarna, H.M. Swartz). Summary. Introduction. Redox Properties of Melanin Relevant to its Interactions with Oxygen. Oxidation of Monomeric Precursors of Melanin. Interaction of Melanin with Ground State Molecular Oxygen. The Ability of Melanin to Quench and Induce Reactive Species Derived from Oxygen. Oxygen-Dependent Photoreactions of Melanin. Degradative Oxidation of Melanin in the Dark. Appendix. 6. Oxidation of Tetrahydrofolates and Tetrahydrobiopterin by Molecular Oxygen (J.A. Blair, G. Farrar). Introduction. Tetrahydrofolate (VI). 5-Methyltetrahydrofolate (III). 10-Formyltetrahydrofolate (V). Polyglutamates. Tetrahydrobiopterin (VII). Biological Implications. 7. Prostaglandin Synthesis and Co-oxidation: Prostaglandin H Synthase-Linked Radical Reactions (G.A. Reed). Introduction. The Arachidonic Acid Cascade. Prostaglandin H Synthase: The Cyclooxygenase Reaction. Prostaglandin H Synthase: Classical Peroxidase Reactions. Non-Classical Peroxidative Oxidations. Commentary. 8. Antioxidants in Vitro and in Vivo (G. Scott). Introduction. Oxidation in Vitro and in Vivo. Mechanisms of Antioxidant Action. 9. Mechanisms of Antioxidant Action in Living Organisms (D.G. Pobedimskij, E.B. Burlakova). Introduction. Mechanisms of Antioxidant Effects on Cell Metabolism. Antioxidants and Their Use in the Biotechnology of Protein Preparations and Biologically Active Substances. Conclusion. 10. Antioxidant Role of Vitamin E (H.H. Draper). Introduction. Lipid Peroxidation. Ozone and Lipid Peroxidation. Nitrogen Dioxide and Lipid Peroxidation. The Dietary Selenium - Vitamin E Interrelationship. Atmospheric Oxidants and their Vitamin E Requirement. 11. Medical Aspects and Techniques for Peroxidases and Catalases (D. Metodiewa, H.B. Dunford). Abbreviations. Introduction. Peroxidases. Catalase. Prostaglandin H Synthase (PGHS). Hydrogen Peroxide. Free Radical Metabolites. Techniques for Medical Use of Catalase and Peroxidase as Therapeutic Agents. 12. Antioxidants and Oncogenesis: Roles in Cancer Causation and Prevention (T.W. Kensler, N.E. Davidson, K.Z. Guyton). Summary. Introduction. Cancer Chemoprotection by Antioxidants. Carcinogenicity of Antioxidants. Subject Index.