Through gripping accounts of extraordinary events and pioneering medicine, Dr Kevin Fong explores how our body responds when tested by the extremes of heat and cold, vacuum and altitude, age and disease. He shows how science, technology and medicine have taken what was once lethal in the world and made it survivable. This is not only a book about medicine, but also about exploration in its broadest sense - about how, by probing the limits of our biology, we may achieve a better appreciation of how our bodies work and what it means to be human.