Marx, Freud, Proust, Einstein, Bernhardt and Kafka. Between the middle of the nineteenth and twentieth centuries a few dozen men and women changed the way we see the world. But many have vanished from our collective memory despite their enduring importance in our daily lives. Without Karl Landsteiner, for instance, there would be no blood transfusions or major surgery. Without Paul Ehrlich no chemotherapy. Without Siegfried Marcus no motor car. Without Rosalind Franklin genetic science would loo..