Robert Wright challenges the conventional view that biological evolution and human history are aimless. Employing game theory - the logic of zero-sum and non-zero-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. Wright takes on some of the past century's most prominent thinkers, including Isaiah Berlin, Karl Popper, Stephen Jay Gould, and Richard Dawkins, arguing that a coolly specific appraisal of humanity's three-billion-year past can give new spiritual meaning to the present and even offer political guidance for the future.