Archives and Special Collections at BGSU contains finding aids, which are detailed inventories of collections (note that finding aids rarely describe individual items in a collection). Finding aids provide historical context as well as dates, provenance (where the collection came from), and information about physical format.
Finding aids often organize archival material into series. Series can be characterized by the type of item (e.g. photographs, letters), by date, or as the donor wished them to be organized.
An example of series in an archival collection: