From the time of his historic expedition to Nanda Devi in the high Himalaya, Charles Houston, M.D., was fascinated by the effects of altitude on the human body. Why do people get sick in the mountains? What are the symptoms of hypoxia -- lack of sufficient oxygen -- that also occurs in everyday life, sometimes chronically due to disease? How can we decrease the incidence of illness and death? This edition incorporates current research on the effects of altitude on humans, and Houston (now deceased) joined forces with an educator and a medical writer in a text made even more accessible for the average reader while retaining the depth of material of particular use to the medical community. This edition of this seminal text added chapters on vision and the eye at altitude, chronic and subacute altitude illness, and the limits to work at altitude (with implications for athletic training). It presents information on genetics and gender differences and more on flight and space travel, on understanding and treating sea-level hypoxic illnesses, and on who can (or should not) go to high altitude, and much more. With an expanded glossary of terms.