These guidelines identify important topics that collection administrators should address in developing adequate security measures and a strategy for responding to thefts. While directed primarily toward special collections in the U.S., many topics are also applicable to general collections and to special collections in other countries. “Special Collections” here refers to repositories containing rare books, manuscripts, archives, and other antiquarian and special materials. “Booksellers” refers to those who sell such materials. In the term “Library Security Officer,” “Library” is understood to mean any special collections repository.