Before tax-supported libraries existed, libraries were organized either privately as stock companies (in which the purchase of a share made one an owner) or as an association of dues-paying members.
When sufficient funds had been raised, these libraries rented or erected buildings, purchased books, and paid their librarians with the proceeds from dues, annual share assessments, or rental fees. Once common across the United States, most membership libraries have either disappeared or been absorbed into public libraries. A few membership libraries continue to thrive, mostly in older cities where they may preserve architecturally significant buildings. Many hold special collections of rare books, prints, maps, photographs, and manuscripts of interest to scholars.