One of the world's experts on chimpanzee behavior considers the nature of culture and its relationship to who humans are. "We define ourselves as the only cultured species, and we generally believe that culture has permitted us to break away from nature. We are wont to say that culture is what makes us human", de Waal explains: "The possibility that animals have culture is the topic I wish to explore in this book." The reviewer for Scientific American recommends that we "look over his shoulder and learn what the animals tell us about ourselves."