In this podcast we discuss how fragile and perishable knowledge and learning can be. We discuss the loss of Latin literature in the West, and the dissipation of the holdings of the Alexandrian library of the Ptolemies. It is clear that even a short period of neglect can result in the loss of a catastrophic quantity of irreplaceable knowledge. Every generation must safeguard and promote the legacy of the past, so that future epochs are not deprived of their cultural inheritance. It only took about 200 years of neglect for the majority of Latin literature to become lost to history.  In the east, the great library of Alexandria, along with that of Pergamum, withered away from a combination of apathy, neglect, and the vicissitudes of time.  What lessons can be learned from these sobering facts?