  There are holes (‘lacunae’) of varying size; surfaces may have been badly abraded in the process of unrolling; ink may have faded, or even vanished altogether; glues used to hold the papyri together and mount them have in some cases penetrated and darkened them. Significant advances in reading the papyri have been made, however, especially by the use of microscopes (first in 1970, then, from 1995, with built-in illumination) and, from 2000, of digital photographs taken mostly in the near-infrared region (‘multi-spectral images’). The problems of continuity posed by the way in which the papyri were opened and read have also recently been addressed in a systematic way. Guglielmo Cavallo’s study (1983) of the scribal hands used in the papyri allowed the texts to be grouped and dated, and it allowed the recognition that numerous pieces had once belonged to the same roll. These technical and philological advances, which have dramatically improved and extended our access to Philodemus’ thought, now require the re-edition of all texts of Herculaneum papyri. There are also newer technical methods which may soon change the situation again by providing three-dimensional images of opened papyri or even reading still rolled-up pieces without opening them.