Direct Descent - Frank Herbert - Bog

Earth has become a library planet for thousands of years, a bastion of both useful and useless knowledge-esoterica of all types, history, science, politics-gathered by teams of "pack rats" who scour the galaxy for any scrap of information. Knowledge is power, knowledge is wealth, and knowledge can be a weapon. As powerful dictators come and go over the course of history, the cadre of dedicated librarians is sworn to obey the lawful government . . . and use their wits to protect the treasure trove of knowledge they have collected over the millennia.