The collection of etchings of the Library is not a proper section, since the vast majorities are integrated in volumes of books, ranging from the first incunabula prints to the 19th century; this is the reason why we find various techniques and styles. Also, we have a wide variety in the locations of printing and the matters covered, which encompass all knowledge.

In regards to thematic , exists a clear prevalence of Humanities, mainly in the 16th century, those of philosophical nature (metaphysics, ethics, logic, politics), religious (ascetic and mystic, Bible, dogmatic and moral theology, patristic, liturgy, hagiography, religious orders, sermons, without forgetting mythology), science (astrology, cosmography, geography, cartography, mathematics, natural history, architecture and engineering, medicine or alchemy, historical (chronology, historiography, history of different countries, biographies, genealogy, heraldry, numismatics, epigraphy), legal, linguistic and literary and other in lesser extent , as visual arts or music, costumes and parties.

From the 17th century we can highlight the Bible in images by the etcher Gérard Jollain or the work by the antiquarian Giovanni Pietro Bellori “Veteres arcus Augustorum triumphis insignes…” by the etchers Petrus Sanctus Bartolus and Petrus Lucatellus. Also we can mention from this century to Marcos de Orozco, Pedro de Villafranca, Claudio Coello, Perret, Noort, Courbes, etc. From the 18th century: Juan Bernabé Palomino or Pedro Pascual Moles, and from the 19th century: Francisco Aznar y García or Antonio Roca Sallent, among many others.

It exist a project for making an inventory and a catalogue of this extensive collection, what has already resulted in the development of three doctoral projects, but undoubtedly, the most promising is the great researching field open to future researchers.