"We know Chaucer in the only way in which the greater authors generally have cared to be known. ...All we need further in the way of fact is some knowledge of the literary conditions of his time. Publication in our modern sense there was none. So long as copies were still made laboriously by hand, circulation was very slow and very limited. Authors wrote for few readers; they had to depend largely for the spread of their works on patrons in positions of influence; and they were never certain that any two copies would be exactly alike. Many books were written in the middle age; but only the most popular of them were circulated in many copies, and sometimes the more copies, the more variations there were from the original. ...authors were at the mercy of the scriveners, or copyists... If the books that a medieval author wrote were thus scarce, dear and inaccurate, so often were the books that he read. The change wrought in this respect by the printing press is too great for us to realize without a strong effort of imagination. ...in Chaucer's time twenty books were a considerable collection, such as would not often be seen outside of the monastic and cathedral libraries ...Nor were even the libraries of cathedrals and monasteries either large or accessible according to our modern habits. ... Adding to the situation the slowness and difficulty of travel, one begins to realize that in the middle age wide reading was easy in only a few centers, and that even in these a man must sometimes have studied not so much what he wanted as what he could get."