Taking everyone from the Renaissance Florence of Leonardo da Vinci to the Floridian rocket launches of Elon Musk's SpaceX, Helen Lewis unravels a word that one would use — without really questioning what it means.

Along the way, she uncovers the secret of the Beatles' success, asks how biographers should solve the Austen Problem, and reveals why Stephen Hawking thought IQ tests were for losers. And she asks if the modern idea of genius — a class of special people — is distorting our view of the world…