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 that accompany them. The subjects of this book are chimpanzees of three generations inhabiting an enriched environment as well as a wild community in West Africa; and phenomena such as face recognition, concept formation, object manipulation, tool manufacture and use, decision making, learning, communication, self-awareness, intentionality, understanding othersa (TM) minds, cooperation, deception, altruism, and reciprocity observed within these groups are reported herein. Unique approaches both in the field and in the laboratory go hand in hand to illustrate the cognitive world of our closest living evolutionary relatives. With a foreword by Jane Goodall.