records from the Lutheran church. The Church Law of 1686 required Lutheran priests to keep parish records containing information on events such as births, marriages, and deaths. These records were used as official census lists for 300 years. As such, these records are notable for the length of time that they span and their accuracy. Preservation The goal of records management is that all records older than 40 years old are catalogued and in order when transferred to the archives for permanent storage. Storage rooms for paper documents are kept at a temperature of 18 degrees Celsius and a relative humidity of 50%. Technical Unit The technical unit is responsible for digitizing and microfilming. They concentrate on frequently requested items and those which are in poor condition. Digitized materials are then made available online. Conservation Documents and other materials are repaired using methods that are reversible without damaging the document. Library The library of the National Archives specialises on archiving, document diplomacy, heraldry and sigillography. Its collections include reference and source books, official publications, literature on the history of Finland and the surrounding areas, justice, management and social science as well as personal and family histories. The library serves primarily research based on archives and documents, customers wanting to retrieve information and on-duty staff. The library is responsible for all literature and other material necessary for customer service and activities at the archives. In its field of expertise, the library of the National Archives is the only library that is a part of Finnish national library network. The library's collection comprises about 334,000 volumes from Finland and abroad and around 200 magazines in various languages. In addition to literature on archiving, history and source books, the library has a large collection of books on heraldry and sigillography, and it also has a historically significant amount of literature printed prior to 1850. The collection is mainly expanded with books on archiving, document management, archive usage and heraldry. Whenever possible, key pieces of literature about basic research of the history of Finland are also acquired. Donations received by the library mainly cover the topics of genealogy and local history. Books in the open collection are freely available for use in the reading rooms. Publications in the closed collection must be ordered for use. Home loans are not allowed. However, it is possible to order material to be delivered to other branches of