Books come at my call and return when I desire them; they are never out of humor and they answer all my questions with readiness. Some present in review before me the events of past ages; others reveal to me the secrets of Nature. These teach me how to live, and those how to die; these dispel my melancholy by their mirth, and amuse me by their sallies of wit. Some there are who prepare my soul to suffer everything, to desire nothing, and to become thoroughly acquainted with itself. In a word, they open the door to all the arts and sciences.