This text describes the role that libraries played in ancient Egypt, Han-dynasty China, the ancient Western Clasical world, the Baghdad of Harun-al-Rashid, and medieval and Renaissance Europe. It continues with the libraries of colonial America, the Library of Congress, university libraries, and today's large public library systems. With the invention of the printing press and the spread of literacy, libraries served the common reader, as well as the priestly and princely elites against which Catholic and Protestant reformers rebelled. In the 20th century, libraries have supported both democratic institutions and have also been tools of Nazi and Soviet totalitarianism. Today, at the dawn of the computer and telecommunication age, it is evident that libraries of the future will play a vital role in the presevation of crumbling books and documents, and in forming new ways of preserving increasingly digitized and technological forms of culture. The text suggests that the role of librarians and libraries in the information age promises to be more important than ever.