MY FIRST THOUGHT on receiving Charles Nicholl’s biography of Leonardo was: who on earth needs another biography of Leonardo? After all, Freud pretty well invalidated the biographical approach to Leonardo’s art by pointing out how exiguous is our knowledge of his upbringing. Kenneth Clark provided one of the great and comprehensive lives of Leonardo in 1939 when he was Director of the National Gallery, and his biography is still in print. And Martin Kemp, Professor of Art History at Oxford, has spent most of his life working on Leonardo, has written widely on his life and work, and is just about to publish another book on him. What, I wondered, could a biographer of Marlowe and Rimbaud have to add to these accounts?