Carlo Rovelli: 'I felt the beautiful adventure of physics was a story that had to be told'

How does a book about theoretical physics sell more than 1m copies? Rovelli explains how he set about sharing his wonder at quantum science

There are two kinds of popular science books. The first kind is for passionate readers. Say you are mad about butterflies. You want a book that gives you all the details about all varieties of butterflies, their lives, habits and colours. You are keen to know everything.

The other kind of popular science book is written for everybody else. Say you never cared much for butterflies, but one day you happened on a book filled with incredible images of their phantasmagorical wings and read an interesting fact, such as how many of them live only for a single day " even though you don't want many details, you suddenly find yourself wanting to learn more.