The image of lost civilizations is compelling: cities buried by drifting sands or tangled jungle, ruin and desolation where once there were people and abundance. Surely few persons can read such descriptions and not sense awe and mystery. Invariably we are spellbound, and want to know more. Who were these people and, particularly, what happened to them? How could flourishing civilizations have existed in what are now such devastated circumstances? Did the people degrade their environment, did the climate change, or did civil conflict lead to collapse? Did foreign invaders put these cities to an end? Or is there some mysterious, internal dynamic to the rise and all of civilizations?