Paleography is the branch of science which deals with ancient writing. As the Greek word for writing comprises a great deal more than the work of pen and ink, paleographical study would be imperfect if it did not take into consideration the ancient inscriptions upon stone and metal which are usually left to numismatists and other archæologists. In a small treatise like the present, no such ambitious and comprehensive treatment is intended. The object is mainly to summarize the results of other men's labor, and to give a general idea of what is known at the present day about the diffusion of the art of writing and the methods of producing books before the sixteenth century.