Life would not exist without sensitive, or soft, matter. All biological structures depend on it, including red blood globules, lung fluid, and membranes. So do industrial emulsions, gels, plastics, liquid crystals, and granular materials. What makes sensitive matter so fascinating is its inherent versatility. Shape-shifting at the slightest provocation, whether a change in composition or environment, it leads a fugitive existence. Physicist Michel Mitov brings drama to molecular gastronomy (as when two irreconcilable materials are mixed to achieve the miracle of mayonnaise) and offers answers to everyday questions, such as how does paint dry on canvas, why does shampoo foam better when you “repeat,” and what allows for the controlled release of drugs? Along the way we meet a futurist cook, a scientist with a runaway imagination, and a penniless inventor named Goodyear who added sulfur to latex, quite possibly by accident, and created durable rubber. As Mitov demonstrates, even religious ritual is a lesson in the surprising science of sensitive matter. Thrice yearly, the reliquary of St. Januarius is carried down cobblestone streets from the Cathedral to the Church of St. Clare in Naples. If all goes as hoped—and since 1389 it often has—the dried blood contained in the reliquary’s largest vial liquefies on reaching its destination, and Neapolitans are given a reaffirming symbol of renewal.