The Document Centre opened to the public in 1990, as a complement to the Historical Archive, previously housed in the castle.
Focusing on local and regional history, the CDoc's library mainly comprises monographs, themed dossiers, periodicals and academic works related to cultural heritage. The collection also contains reference works, such as encyclopaedias, dictionaries and other general monographic studies.
Some of the books in the library were donated by intellectuals from the municipality, such as José António Madeira and Pedro de Freitas, among others. The remainder were either purchased or acquired through exchanges. Currently, the reading room library contains around 3,000 books.
The Cândido Guerreiro and Condes de Alte libraries in Alte Museum also form part of the CDoc's bibliographic collection.
Apart from housing the library, the CDoc's reading room can also be used by those who want to consult the documents in its collection, particularly periodicals and photographs, among others.