This essay will analyze how library organizations, such as the American Library Association, and individual librarians responded to the pressure placed on libraries during the McCarthy era to deal with alleged subversion. Although libraries have always been the target of censors, it was during the first decade of the Cold War that those Americans most fearful of Communist subversion swept up large numbers of their fellow citizens in a crusade to rid libraries of Communist influence. That effort by the self-proclaimed “loyal Americans” to save libraries put more than just library collections under the microscope. The librarians themselves were scrutinized to ensure that they harbored no troubling past or present connections to radical political groups. Pressure groups examined library services closely as well, keeping an eye out for subversion in library exhibits or making sure that controversial books were only available by request, not on open shelving.