The need to describe the world around us is an impulse as old as the earliest cave wall depictions of running horses and wounded bison. In this descriptive enterprise we have consistently found nature to be a valuable and inspiring companion, and over the centuries, as we moved beyond simple narrative to the complex, exhortative inventions of allegory, nature has reciprocally grown with us, giving us a crucial and familiar framework to help us to know our place in the universe. As a consequence of this evolution, the human imagination can claim innumerable--often epic--accounts built on...