In library science, special collections (Spec. Coll. or S.C.) are libraries or library units that house materials requiring specialized security and user services. Special collections can be found in many different organisations including research libraries, universities, colleges, schools, national libraries, public libraries, museums, art galleries, archives, historic houses, cathedrals, subscription libraries, learned societies, hospitals, companies and monasteries.
Materials housed in special collections can be in any format (including rare books, manuscripts, photographs, archives, ephemera, and digital records), and are generally characterized by their artifactual or monetary value, physical format, uniqueness or rarity, and/or an institutional commitment to long-term preservation and access. They can also include association with important figures or institutions in history, culture, politics, sciences, or the arts. Some special collections are recognised as being of global importance; the UNESCO Memory of the World Register includes documentary heritage material.