From an evolutionary perspective, understanding chimpanzees offers a way of understanding the basis of human nature. This book on cognitive development in chimpanzees is the first of its kind to focus on infants reared by their own mothers within a natural setting, illustrating various aspects of chimpanzee cognition and the developmental changes accompanying them. The subjects are chimpanzees of three generations inhabiting an enriched environment, as well as a wild community in West Africa. There is a foreword by Jane Goodall and 26 color photos of chimpanzees in the laboratory and in the field in West Africa are included.