The meaning of the word “hypothermia” has Greek origins and roughly translates to “less heat.” Its symptoms can be deadly - shivering, followed by confusion, irrationality, and even the illusion of feeling hot. But hypothermia has another side - it can be therapeutic. In Out Cold, science writer Phil Jaekl chronicles the underappreciated story of human innovation with cold, from Ancient Egypt, where it was used to treat skin irritations, to 18th-century London, where scientists used it in their first explorations of suspended animation. Throughout history, physicians have used cold to innovate life extension, enable distant space missions, and explore consciousness. Hypothermia may still conjure macabre images, like the bodies littering Mt. Everest and disembodied heads in cryo-freezers, but the reality is that modern science has invented numerous new life-saving cooling techniques based on what we’ve learned over the centuries. And Out Cold reveals a surprisingly warm future for this chilling state.