Examining the molecular structure of our DNA, we find that only a small one per cent makes us different from chimpanzees; chimpanzees and bonobos are closer to humans than to gorillas, and the three great African apes show more similarities with us than with orang-utans. Mollison accepted the idea of a "gradual" evolution and tried to make in photography a kind of family tree, not of close relatives but not very distant ones either: a series of "similar ones", all great apes photographed with exceptional skill in tight, continuous close-ups, shows how thin the line dividing species can be. All the portraits come with notes and technical information.