To watch a curious young macaque explore and manipulate his immediate surroundings must surely delight and amaze us all. The monkey selects a particular objectfor scrutiny, reaches out and grasps it, handles it delicately with the fingers or more forcibly with the hand, scans the various surfaces with the fin ger pads, and finally identifies it. If we compare this monkey's adroitness and discriminative capacities with our own, at once we have a concise statement of important biological similarities and differences among primates. While there are species diffe rences in the functional anatomy...