Molecular hydrogen (H2) has emerged as a promising therapeutic and preventive medical gas. Hydrogen gas has garnered significant attention in recent years due to its remarkable antioxidant and anti-inflammatory properties. H2 exhibits exceptional pharmacokinetics, swiftly traversing cellular biomembranes to access subcellular organelles indirectly regulating hormones and cytokines through various signal transduction pathways. H2 has the potential to address a wide range of issues, including clinical medical treatment in the areas of healthcare: myocardial ischemia, heart failure, cardiac arrest, metabolic syndrome, advanced-stage cancer, inflammatory diseases, Alzheimer's dementia, aging-related disorders, sports activities, and even beauty, agriculture, etc.Selected world-known authors in the field provide readers with a comprehensive overview of molecular hydrogen's remarkable effects and its physical, chemical, and therapeutic properties and potential in biomedical applications. This contributed volume fills the current gap in information and is intended for everyone who wants to be better informed about the wide possibilities of using molecular hydrogen. However, it is mainly intended for use aby medical students, physiologists, pharmacologists, physicians, and other healthcare personnel who can use molecular hydrogen to improve the health of everyone who needs it.