You may have been in a room in which there was a window that looked out on a lovely bay of the sea or a green valley that wound away among mountains. And in the wall of that room opposite to the window there may have been a lookingglass. And as you turned away from the window you suddenly caught sight of that sea or that valley, all over again, in the looking glass. And the sea in the mirror, or the valley in the mirror, were in one sense just the same as the real ones: yet at the same time they were somehow different - deeper, more wonderful, more like places in a story: in a story you have never heard but very much want to know.