a group of scholars thinks that there may be another library yet to be discovered in the villa of the papyri at herculaneum. this is surely a tantalizing possibility (LvBW). here are a couple of excerpts:
All knowledge of the great house was lost until 1738, when workmen sinking a well shaft encountered a mosaic floor. It was too deep to excavate; instead, over the next 20 years under the supervision of Karl Weber, a Swiss military engineer, a network of tunnels was hewn through the debris clogging the great peristyle, the atrium and the Olympic-sized swimming pool. Cartloads of treasures were brought to the surface, destined for the art collection of the King of Naples.
Throughout this time, mingled with the sculptures and glassware, workmen retrieved what looked like lumps of coal which they unthinkingly dumped in the sea. It was not until 1752 and the discovery of an intact library lined with 1,800 rolls of papyrus, that the excavators realised that what they had been throwing away were carbonised books. The site has since been known as the Villa of the Papyri.
from the 1800 rolls discovered previously, some interesting things have been found:
The author chiefly represented in the collection is Philodemus, an Epicurean philosopher of the 1st century BC who taught Virgil, the greatest Latin poet, and probably also Horace. He may indeed have given lessons to both beneath the porticoes of the Villa of the Papyri, for it is known that Philodemus was employed in the household of a powerful Roman senator, Lucius Calpurnius Piso Caesoninus, father-in-law of the dictator Julius Caesar. And it is now regarded as almost certain that Piso — who died more than a century before the eruption of Vesuvius — was the original owner of the Villa of the Papyri.
Apart from the texts of Philodemus, hundreds of other lost works of Greek philosophy — including half of Epicurus’s entire opus, missing for 2,300 years — have been rediscovered. Among them is a treatise by Zeno of Sidon, who Cicero saw lecture in Athens in 79BC. According to Richard Janko, professor of classics at Michigan University [sic]: “This is the first copy of Zeno’s writings to come to light; they had all been lost in later antiquity.”
the late professor marcello gigante thinks that the extant collection represents perhaps only half of the villa's collection.
read all about it here.