The Library of old and rare books of the College is a rich collection of interesting texts that are not exclusively religious. The Library was created during the 1840s as an essential resource for the eduction of young aristocrats or members of the ruling classes. For this reason as early as 1842 the Library purchased the volumes of the College Ghiglieri of Finale Ligure to add to those which were already a part of the Barnabite's Library in Moncalieri.

In 1868, with the suppression of the religious orders and the transfer of Library collections into public hands, the Royal College Library obtained permission to allow its volumes to remain in their original location even though they became the property of the City. Certain of this agreement, in 1870 the Barnabites purchased, for the considerable sum of one thousand four hundred francs, the books which had belonged to the deceased canon Giuseppe Filiberto Oggero, an extensive collection that bear witness to the canon's eclectic interests.

Quite soon it became necessary to enlarge the Library using adjacent rooms where the patristic and theological volumes previously belonging to the Collegio San Dalmazzo of Turin, founded by the Barnabites in 1609, were placed; noteworthy among these volumes are those which were the property of the theologian Giovanni Pagnone or the priest Giuseppe Michele Bessone, former member of the Academy of Sciences and in 1824 rector and librarian of the Royal University of Turin, and personally inscribed by them.

The books in the Library are arranged on the shelves according to size rather than subject or author's name; this has meant the dismemberment of the different collections in the Library's several rooms, with the exception of the volumes which belonged to the Princess Maria Clotilde of Savoy and to the American author John Lawson Stoddard.

The project for the expansion of the Library continued during the 20th century;in addition, beginning in the 50s the entire Library was re-arranged and catalogued initially by Father Rodolfo Pezzani and later by Father Domenico Frigerio.

Much more could be said about the scientific publications which Father Denza so loved, the writings of fathers Gerdil, Colombo and Boffitto, clear testimony of that cultural fervor that has always animated the Barnabites. This is a Library which is not only religious in content but also ready to accommodate the poems of Coleridge, the philosophical treatises of Kant and the many volumes made more precious by their delicate bindings in red maroccan leather or in parchment. A world whose fascination has been preserved intact.