Helgoland is a craggy German island in the North Sea. Barely bigger than a few fields, it reaches high above the water on precipitous cliffs and is famous for its sweet air. It has a town and a harbour, and the 1,000-odd inhabitants speak a distinct dialect. In the summer of 1925, the 23-year-old physicist Werner Heisenberg went there to sort out his
hay fever and solve the problem of reality.

Helgoland is a slightly misleading title for Carlo Rovelli’s inspiring, chaotic, delightfully unsatisfactory book of popular quantum physics.