Robert Wright challenges the conventional view that biological evolution and human history are aimless. Employing game theory - the logic of zero-sum and nonzero-sum games - he isolates the impetus behind life's basic direction: the impetus that, via biological evolution, created complex, intelligent animals, and then via cultural evolution, pushed the human species towards deeper and vaster social complexity. In this view, the coming of today's independent global society was on the cards - not quite inevitable, but, as Wright puts it, so probable as to inspire wonder.