Books that are infrequently used or are too fragile for open stacks are transferred to the off-site storage facility at the WRLC Center, in Upper Marlboro, MD, leaving much needed room in the Mullen Library stacks for new acquisitions and for the more frequently used books. Before transferring books, the holdings records are updated to assure that the books are still findable through the library catalog. Fragile books are provided preservation enclosures (envelopes or boxes) for protection.