This book reviews the major biochemical and biological properties of the lactoperoxidase system including both the bovine milk and human salivary enzymes. It focuses on the basic chemistry of peroxidase-catalyzed reactions and clinical applications of peroxide system antimicrobial effects.1. The Biological Significance of the Nonimmunoglobulin Defense Factors 2. The Chemical Structure of Lactoperoxidase 3. Products of Lactoperoxidase-Catalyzed Oxidation of Thiocyanate and Halides 4. Steady-State Kinetics of Lactoperoxidase-Catalyzed Reactions 5. Genetic Variation of Salivary Peroxidase 6. The Peroxidase System in Human Secretions 7. The Lactoperoxidase System of Bovine Milk 8. Biochemistry of Peroxidase System: Antimicrobial Effects 9. Bacterial Hydrogen Peroxide Production 10. Effect of Sugars and Sugar Alcohols on Salivary Peroxidase 11. Activation of the Salivary Peroxidase Antimicrobial System: Clinical Studies 12. Antibody Targeting of the Antimicrobial and Antitumor Activity of the Peroxidases