Underlying the anthropological study of man is the principle that there is a reality to which man must adapt if he is to survive. Reproduce, and to perpetuate himself. Populations must adapt to the realities of the physical world and maintain a proper "fit" between their biological makeup and the pressures of the various niches of the world in which they seek to live. Social groups--where culture is found--must develop adaptive mechanisms in the organization of their social relations if there is to be order, regularity, and predictability in patterns of cooperation and competition and if...