After writing books about the science of sleep, the history of human blood, and the story behind Gray’s Anatomy—as well as a warm and poignant memoir of his late partner, Oliver Sacks—Hayes’s latest work is about the experience of exercise. He describes starting his research at a local library, only to find that the older books he was interested in were no longer around. This led Hayes to the New York Academy of Medicine Historical Collections library, where he was introduced to what he calls a magical book from the Renaissance, De Arte Gymnastica by Girolamo Mercuriale (1573). Hayes followed Mercuriale’s lead to libraries and archives in England and France and even on a trip to Greece to visit the sites of the first Olympic games. Hayes went on to explore great writers’ texts about exercise, including musings by Greek poet Hesiod and Bohemian novelist Franz Kafka. Hayes’s book brings the narrative up to the 20th century with an exploration of modern exercise gurus like Jack LaLanne and Jane Fonda. VERDICT At once a book about exercise history, and a travelogue, a literary discovery tour, and another of Hayes’s personal and exhilarating memoirs.