The library is one of the most important historical libraries in Tuscany. Established in 1786 on the death of the erudite Volterran Monsignor Mario Guarnacci who left his collection of about 7.000 volumes to “the citizens of Volterra”. Throughout the centuries, purchases and donations have increased the number to 50.000 volumes.
The collection comprises 514 manuscripts (including extremely valuable illuminated codices such as the Epithalamium composed by G.F. Marliano for the wedding ceremony of Bianca Maria Sforza and Giovanni di Mattia Corvino and the famous miniature portrait of the great king of Hungary ) 273 incunabula ( including the only example of the Doctrinal of Alessandro de Villa Dei printed in Bologna at Bazalerius de Bazaleriis in 1489 and a splendid Breviarium Romanum on parchment printed in Venice by Jenson in 1478 and illustrated with magnificent miniatures)and more than a 1.000 16th century volumes.
There are many 17th and 18th century works on theology, literature, history, botanics, medicine,
geography and humanistic disciplines. Noteworthy is the rich section on the local history of Volterra and its territory.
The library also houses entire private collections such as The Funaioli collection (about 2.500 volumes 19th - 20th century), the Pacciani Collection ( 1450 volumes 19th century), and distinguished archives such as the Diplomatic collection ( about 3.000 parchments from 907 to 1756), the Maffei Archive (258 files 15th - 19th century) The Riccirelli Papers (16th-19th century).
The National Guard Archive (1860-1870), the Archive of the Accademia dei Riuniti(19th century).
The Archive and library of the Accademia dei Sepolti and the valuable Collection Aulo Persio Flacco and the interesting Herbal compiled by the Volterran physician Gaspero Amidei.