The only means by which humanity can have a history and a continuing consciousness of itself.

From My Belief: Essays on Life and Art, a collection of essays by Hermann Hesse.  The Magic of the Book is an essay from 1930.  

We need not allow ourselves to be robbed of the agreeable feeling of progress attained, instead we will rejoice that reading and writing are no longer the prerogatives of a guild or caste. Since the invention of the printing press the book has become an object of general use and luxury distributed in huge quantities. Large printings make possible low book prices and therefore every country can make its best books (the so-called classics) available to those in modest circumstances. Then too we will not grieve very much over the fact | that the concept “book” has lost almost all its former splendor and that very recently the book seems to have sacrificed even more of its worth and attractiveness in the eyes of the crowd because of the cinema and the radio. And yet we need not fear a future elimination of the book. On the contrary, the more that certain needs for entertainment and education are satisfied through other inventions, the more the book will win back in dignity and authority. For even the most childish intoxication with progress will soon be forced to recognize that writing and books have a function that is eternal. It will become evident that formulation in words and the handing on of these formulations through writing are not only important aids but actually the only means by which humanity can have a history and a continuing consciousness of itself.