That paper, a much softer material than either stone or wood, won out as the guardian of the written word is a remarkable materials story. It is the thinness of paper that proves to be one of its great advantages, allowing it the flexibility to survive continuous handling, but when stacked together in book form becoming stiff and strong—essentially a re-formed block of wood. With the use of hard covers to hold it all together, the book is a fortress for words for thousands of years.
