PREFACE ad tendency to concentrate attention too much on what is called the 'sovereign state'. But states are merely territorial groups within a larger political system in which their relations are defined by war or its possibility, treaties, and international law. A political system of this kind, such as now exists in Europe, of sovereign nations linked by international relations, is only one type of political system. Political theory and political practice (including colonial administration) have often suffered by reason of this type of system being set up, consciously or unconsciously, as a norm. There is a second aspect of political structure. The social structure of any society includes some differentiation of social role between persons and between classes of persons. The role of an individual is the part he plays in the total social life— economic, political, religious, &c. In the simplest societies, there is little more than the very important.differentiation on the basis of sex and age and the non-institutionalized recognition of leadership in ritual, in hunting or fishing, in warfare, and so on, to which we may add the specialization of the oldest profession in the world, that of the medicine man. As we pass from the simpler to the more complex societies we find increasing differentiation of individual from individual and usually some more or less definite division of the community into classes. As political organization develops there is an increasing differentiation whereby certain persons—chiefs, kings, judges, military commanders, &c.—have special roles in the social life. Each such person may be said to hold or fill an office—administrative, judicial, legislative, military, or other. The holder of an office in this sense is endowed with authority, and to the office there attach certain duties and also certain rights and privileges. In Africa it is often hardly possible to separate, even in thought, political office from ritual or religious office. Thus in some African societies it may be said that the king is the executive head, the legislator, the supreme judge, the commander-in-chief of the army, the chief priest or supreme ritual head, and even perhaps the principal capitalist of the whole community. But it is erroneous to think of him as combining in himself a number of separate and distinct offices. There is a single office, that of king, and its various duties and activities, and its rights, prerogatives, and privileges, make up a single unified whole.