Just before Christmas in 2008, a woman tapped me on the shoulder while I was shopping in the local supermarket and asked if I’d written a book called Quantum. I confessed that I had. As we chatted I discovered that her daughter was in the same class as my six-year-old and that her grandfather was Max Born, one of the pioneers of quantum mechanics. She had purchased two copies of my book and had given one to her father, Gustav. Some time later I received a letter from Professor Born that led to a memorable lunch at the Royal Society.