An incunabulum is a book, single sheet or image that was printed before the year 1500 in Europe. These are usually very rare and fragile items whose nature can only be verified by experts. The origin of the word is the Latin in cuna, meaning "in the cradle".
McCune Room at JFK Library houses a superb collection of rare and unique books, printing equipment and binding tools left as a bequest to the City of Vallejo by Dr. Donovan J. McCune.