Man has conquered Everest, been to the bottom of the deepest ocean, and even walked on the Moon by understanding pressure and oxygen. But the one area of life the technology has not influenced is the practice of medicine. Billions have been spent researching drugs to treat the brain and they have failed; drug companies are closing their neuroscience laboratories. This is because there is no substitute for oxygen. As the most astonishing discovery since DNA was unraveled has shown, oxygen, the gas in the air we all breathe, controls our most important genes. If we are sick or seriously injured and in intensive care, the amount of oxygen we can be given is limited by the weather. Without a simple pressure chamber, we are forced to accept a variation of more than 10% when just 2% more oxygen on the summit of Everest can mean the difference between life and death. We have already engineered the solution; the technology used in aircraft that sustains us flying at 40,000 feet can facilitate medical recovery safely on the ground. This book follows the human journey from conception to old age and presents evidence amassed over more than a century that can transform the care of patients with birth injury, head trauma, multiple sclerosis, stroke, and even reverse decline in old age. There is no more necessary and scientific action than to correct a deficiency of oxygen, especially in the brain and it is simple to give more.