Carlo Rovelli, one of the world's most famous theoretical physicists, captivated millions of readers with his extraordinary view of the cosmos. In Heligoland, he explores the enduring mystery of quantum theory. The quantum world that Rovelli describes is as beautiful as it is unnerving. Helgoland is a treeless island in the North Sea, where twenty-three-year-old Werner Heisenberg made a decisive breakthrough in the creation of quantum mechanics, marking the beginning of a century of scientific revolution.