The trilogy tells of our world and a parallel one in which it was the Homo sapiens who died out and the Neanderthals who became the dominant intelligent species. This powerful idea allows Sawyer to examine some of the deeply rooted assumptions of contemporary human civilization dramatically, by confronting us with another civilization, just as morally valid, that has made other choices. In Humans, Neanderthal physicist Ponter Boddit, a character you will never forget, returns to our world and to his relationship with geneticist Mary Vaughan, as cultural exchanges between the two Earths begin.