"I have never had illusions about the value of my individual contribution! I realized early that what a man or a woman does is built on what those who have gone before have done, that its real value depends on making the matter in hand a little clearer, a little sounder for those who come after. Nobody begins or ends anything. Each person is a link, weak or strong, in an endless chain. One of our gravest mistakes is persuading ourselves that nobody has passed this way before."