Hydrogen peroxide is the compound the body already makes. Mitochondria produce it continuously in every cell. Phagocytes release it as their primary tool for breaking down waste. The thyroid manufactures it as part of hormone synthesis. Colostrum delivers it to the newborn at concentrations that would be considered clinically significant if administered as therapy. It is chemistry the body was already conducting before any protocol was developed. The gap between what medicine says about the compound and what the compound actually does is the gap that produced the situation this book documents. It was not suppressed for lacking clinical utility. It was suppressed precisely because its clinical utility threatened the pharmaceutical direction that captured medicine across the twentieth century. This book recovers the practice. It draws on Edward Rosenow at the Mayo Clinic, Charles Farr's intravenous protocols, William Campbell Douglass II's 1990 compilation, Walter Grotz's layperson-bridge role, Bill Munro's spray-pump work, and the current-generation systematization of Thomas Levy and David Brownstein. Ten chapters cover the body's own hydrogen peroxide chemistry, the four therapeutic processes, the oral cavity as terrain compromise seat, the 1918-20 events medicine attributed to Spanish influenza, and the historical arc of the tradition. Four appendices give the complete protocol reference by route, condition-by-condition reference, a practitioner directory, and a nine-episode century of institutional suppression. The compound is old, well-studied, inexpensive, and available. What follows is what the tradition has to say about how to use it. Second Edition — Revised and Expanded.