In his beautifully written prose, Dr Jonathan Reisman - physician, adventure traveller and naturalist - allows readers to navigate their insides like an explorer discovering a new world. Through his offbeat adventures in healthcare and travel, Reisman discovers new perspectives on the body: a trip to the Alaskan Arctic reveals that fat is not the enemy, but the hero; a stint in the Himalayas uncovers the boundary where the brain ends and the mind begins; and eating a sheep's head in Iceland offers a lesson in empathy. By relating his experiences in far-flung lands and among unique cultures back to the body's inner workings, he shows how our organs live inextricably intertwined lives in an internal ecosystem that reflects the natural world around us.