The past itself, as historical change continues to accelerate, has become the most surreal of subjects—making it possible, as Benjamin said, to see a new beauty in what is vanishing. From the start, photographers not only set themselves the task of recording a disappearing world but were so employed by those hastening its disappearance. (As early as 1842, that indefatigable improver of French architectural treasures, Viollet-le-Duc, commissioned a series of daguerreotypes of Notre Dame before beginning his restoration of the cathedral.) “To renew the old world,” Benjamin wrote, “that is the collector’s deepest desire when he is driven to acquire new things.” But the old world cannot be renewed—certainly not by quotations; and this is the rueful, quixotic aspect of the photographic enterprise.