The book cites the most recent scientific findings to provide a radically different approach to the formation and background of cancer, and also lays down the scientific foundations for a new, effective methodology of curing cancer. The author began his research in the early 1990s while investigating the role that deuterium (heavy hydrogen) plays in regulating biological and physiological processes. A number of leading universities and research institutes worldwide have joined the groundbreaking research. The book examines the most common conventional treatment methods in oncology and introduces the most effective combinations of treatments while providing detailed instructions in using deuterium depletion. Also discussed are deuterium depletion's mechanism of action, the most important factors affecting effectiveness, and the main considerations when using the method. The method's therapeutic potential is demonstrated through sixteen types of cancer, results from clinical trials, and specific case studies. One crucially important chapter describes how to use deuterium depletion to foster a healthy lifestyle. The last chapter contains recommendations for use, providing a helpful guide for health-conscious individuals or those struggling with the disease. The book strives to keep a balance between being easy to read or speaking in laymen's terms while providing a professional introduction of the research and clinical application to researchers and doctors. It discusses the treatment method based on deuterium depletion, which offers a tool of curing cancer and other chronic diseases, while also being more efficient and milder than any other oncotherapy up to now.