In A Canticle For Leibowitz, the Albertian Order of Leibowitz was a monastic community in the desert of what you or I would call the southwestern United States. Their patron saint was their founder, Saint Leibowitz the Engineer, the process of whose canonization makes up part of the story. "Albertian" refers to Saint Albertus Magnus, patron saint of scientists and teacher of Saint Thomas Aquinas.
The purpose of the AOL was to preserve knowledge dating from before the Flame Deluge into the dark days following. To that end, the monks of the Order were either "memorizers" or "bookleggers." Memorizers, as the name implies, would memorize the contents of books and papers, much as in Ray Bradbury's Fahrenheit 451. Bookleggers would collect old books and smuggle them from out of the reach of the simpleton mobs to safe caches. Even after human society stabilized somewhat long after the Flame Deluge, each monk was still designated with one of these two roles, and was bound to always carry a book with him.