Those who wish, in the interest of morality, to reduce Leonardo, that inexhaustible source of creative power, to a neutral or sexless agency, have a strange idea of doing service to his reputation.

Only the bad artists of the nineteenth century were frightened by the invention of photography; the good ones all welcomed it and used it.

Few people can look at a painting longer than it takes to peel an orange and eat it.

The illustrator is essentially a reporter: his subjects come from the outside, lit by a flash. A subject comes to the classical artist from inside, and when he discovers confirmation of it in the outside world he feels that it has been there all the time.

Great works of art can be produced in barbarous societies - in fact the very narrowness of primitive society gives their ornamental art a peculiar concentration and vitality. At some time in the ninth century one could have looked down the Seine and seen the prow of a Viking ship coming up the river. Looked at today in the British Museum, it is a powerful work of art; but to the mother of a family trying to settle down in her little hut, it would have seemed less agreeable - as menacing to her civilisation as the periscope of a nuclear submarine.

Devotion to the facts will always give the pleasures of recognition; adherence to the rules of design, the pleasures of order and certainty.

It is often said that Leonardo drew so well because he knew about things; it is truer to say that he knew about things because he drew so well.