The National Library sits on Republic Square, beside the Grandmaster's Palace, and feels like one of Valletta's more evocative interiors. Its great archive holds records of the Knights of St John, stretching from the Crusades to Napoleon's arrival in Malta in 1798.
Only part of the library is normally open to the public, and visitors may need photo ID to enter. It is a short stop, but a good one if you like old reading rooms, archives, and the institutional memory of the Knights.