Life is controlled by chemistry. Chemistry is not the whole life but the life is totally chemistry. Chemistry is a key to biology. Nothing in biology can be understood without chemistry and chemical reactions. There are many factors controlling biochemical reactions, however the most intriguing is the magnetic field. The ability to respond to magnetic fields is ubiquitous and universal among the five kingdoms of organisms. Magneto-biology is a field of knowledge which considers phenomena accompanying the influence of magnetic fields, permanent and alternating, on the biological systems at all levels: molecular, cellular, and whole organism. There is no doubt that magnetic fields do the human health and feeling of well-being; the latter is a key factor stimulating both social and scientific interest in magneto-biology. This book considers numerous biological and biomedical effects of the two magnetic fields: internal fields created by magnetic nuclei, and external magnetic fields, both permanent and oscillating. It critically summarizes magnetic effects on the biological clocks, biological compass for orientation and navigation of migrating animals, the influence of cells phones on the health. It demonstrates magnetic and isotope effects on the food chains and metabolism, ecology and epidemiology. It explains the origin of trans-cranial magnetic stimulation of cognitive processes to prevent neurodegenerative disorders; it enlightens magnetic stimulation of the ATP synthesis and protein phosphorylation, magnetic control of the DNA synthesis and gene expression. It shows how magnetic fields can be used to eliminate ATP deficiency at cardiac diseases and how to use magnetic stable isotope ions as the medical agents against hypoxia and cardiac insufficiency, as a means for controlling cell proliferation and stimulating destruction and apoptosis of the cancer cells. The uniqueness of this book is that it is focused on the chemical biology and medicine, on the discovery and analysis of chemical magneto-dependent mechanisms. This book gives a collection of scattered information, its critical analysis, generalization and explanation of physics and chemistry of magneto-biological effects as a basis for the deliberate usage in medicine (for the trans-cranial magnetic stimulation of cognitive processes and genetics, in particular).