For more than a century, certain extraordinary men and women have worked in photography with the unmistakable authority of genius. Each of them has produced unforgettable images, and not once or twice, but again and again, and often throughout the change and evolution of a lifetime. Each is like an eye which, once opened on the universe, cannot be closed again. One after another, they tell us of the curious, intense and vital experience of working in photography, of its challenges, of the stages of growth it demands, the sudden revelations it presents. From their testimony there emerges a concept of photography as a medium that is very different from the casual and rather stereotyped impressions most of us have held till now.