Got a spare million or two lying around? Then maybe you'll want to drop by Christie's auction house and pick up an original copy of Copernicus' De Revolutionibus Orbium Coelestium. Need I say it? Holy Haleakala! This is the book that forever changed the world, in which Copernicus proposed a new model of the solar system where the Sun was at the center, not the Earth. I hear Galileo had something to say about that based on this book, too. Man, how awesome would it be to have something like that? After all, I <3 heliocentrism.