A book I am reading notes that the idea of being "modern" originated in the Middle Ages. It is odd to think of flagellating monks and Canterbury pilgrims regarding themselves as modern. Even odder to think how, like them, we moderns will one day seem medieval. In a few hundred years, today's books will appear silly with their solemn talk of the modern world. A book about recent trends in capitalism will sound as contemporary as a book about recent trends in feudalism. "The War on Terrorism" will have the ring of "the War of the Roses." Solar energy will be as cutting edge as firewood.