QUOTE : The revolution caused by the sharing of experience and the spread of knowledge had begun. The Chinese, a thousand years ago, gave it further impetus by devising mechanical means of reproducing such marks in great numbers. In Europe, Johann Gutenberg independently, though much later, developed the technique of printing from movable type. Today, our libraries, the descendants of those mud tablets, can be regarded as immense communal brains, memorising far more than any one human brain could hold. More than that, they can be seen as extra-corporeal DNA, adjuncts to our genetic inheritance as important and influential in determining the way we behave as the chromosomes in our tissues are in determining the physical shape of our bodies. It was this accumulated wisdom that eventually enabled us to devise ways of escaping the dictates of the environment. Our knowledge of agricultural techniques and mechanical devices, of medicine and engineering, of mathematics and space travel, all depend on stored experience. Cut off from our libraries and all they represent and marooned on a desert island, any one of us would be quickly reduced to the life of a hunter-gatherer.