Many consider libraries to be immutable institutions, deeply entrenched in the past, full of dusty tomes and musty staff. In truth, libraries are and historically have been sites of innovation and disruption. Originally presented at the Library History Seminar XII: Libraries: Traditions and Innovations, this collection of essays offers examples of the enduring and evolving aspects of libraries and librarianship. Whether belonging to a Caliph in 10th-century Spain, built for 19th-century mechanics, or intended for the segregated Southern United States, libraries serve as both a reflection and a contestation of their context. These essays illustrate that libraries are places of turmoil, where real social and cultural controversies are explored and resolved, where invention takes place, and where identities are challenged and defined, reinforcing tradition and commanding innovation.