A treasure chest in the heart of the Vatican City that collects unique testimonies for the cultural and religious history of humanity. From the 4th century onwards, a scrinium of the Roman Church, which had the dual function of a library for storing books and an archive for documents, is attested in Rome in the basilica of San Giovanni in Laterano. Following its history from its beginnings, this volume focuses above all on its transformation into the Library of the Popes, after their definitive transfer to the Vatican in the 15th century. A first venue of the Vatican Library, inside the Apostolic Palace near St. Peter's, was set up by the founder Niccolò V (1447- 1455); after a century, however, the space was no longer sufficient to contain what had now become the largest library in the world, and Sixtus V (1585-1590) decided to have the Salone Sistino built, a new location in the Cortile del Belvedere. A monumental jewel, which extends over a thousand square meters, all decorated with frescoes dedicated to the history of libraries and ecumenical councils, and with depictions of the inventors of the alphabets and of the Rome of the time. From the end of the nineteenth century, then, the Library doubled its reading spaces and increased its deposits tenfold, up to the current 80,000 manuscripts, about 1,600,000 prints (including almost 9,000 incunabula), engravings, drawings, coins and medals. The absolute protagonists of this unique place in the world are naturally the books, or, if you like, the codices, the parchments, the most famous manuscripts for their cultural contribution, for the preciousness of the document and for their artistic value. These protagonists are mentioned and commented on according to the chronology of their entry into the Library, so the last is the Papyrus Bodmer XIV-XV, dated between the 2nd and 3rd century AD, with the Gospels according to Luke and John.