How does the body react to months spent in zero gravity, to the Arctic winter, to high-altitude air with low oxygen content, to extreme heat or lack of fluid? What happens from working long periods underground or in microgravity, and why do body temperature, blood pressure, and heart rate change relatively minimally under such conditions? Space medicine and physiology specialist Hanns-Christian Gunga explains what happens to the human body under extreme physical and psychological stress. In his authoritative opinion, in order to better understand the “unknown essence” of a person, a holistic approach is needed, which covers many areas of knowledge, from physiology and psychology to geology, astronomy, paleontology, and which always puts the human body at the center of attention. “In this In this book I will talk about such research that is carried out in truly adventurous circumstances. We will get acquainted with the amazing adaptive capabilities of humans and animals, as well as their physiological basis, which I will try to describe in as accessible and understandable a language as possible, as far as they have been known so far.” (Hanns-Christian Gunga)