The ancient city of Oxford is a picturesque but cluttered little town of narrow cobblestoned streets lined with gothic stone buildings and souvenir shops. When I was there in September, just before the start of Michaelmas term, tourists were thick on the ground, hurrying from the Ashmolean Museum to the Bodleian Library, some waving wands on what were plainly Harry Potter walking tours. It is easy for the casual visitor to miss the real beauties of Oxford, which are mostly inside the walls, hidden like pearls in elaborate stone shells.